perf bpf: Ignore deprecation warning when using libbpf's btf__get_from_id()
Perf code re-implements libbpf's btf__load_from_kernel_by_id() API as
a weak function, presumably to dynamically link against old version of
libbpf shared library. Unfortunately this causes compilation warning
when perf is compiled against libbpf v0.6+.
For now, just ignore deprecation warning, but there might be a better
solution, depending on perf's needs.
Ian Rogers [Sat, 18 Sep 2021 05:44:40 +0000 (22:44 -0700)]
libperf evsel: Make use of FD robust.
FD uses xyarray__entry that may return NULL if an index is out of
bounds. If NULL is returned then a segv happens as FD unconditionally
dereferences the pointer. This was happening in a case of with perf
iostat as shown below. The fix is to make FD an "int*" rather than an
int and handle the NULL case as either invalid input or a closed fd.
$ sudo gdb --args perf stat --iostat list
...
Breakpoint 1, perf_evsel__alloc_fd (evsel=0x5555560951a0, ncpus=1, nthreads=1) at evsel.c:50
50 {
(gdb) bt
#0 perf_evsel__alloc_fd (evsel=0x5555560951a0, ncpus=1, nthreads=1) at evsel.c:50
#1 0x000055555585c188 in evsel__open_cpu (evsel=0x5555560951a0, cpus=0x555556093410,
threads=0x555556086fb0, start_cpu=0, end_cpu=1) at util/evsel.c:1792
#2 0x000055555585cfb2 in evsel__open (evsel=0x5555560951a0, cpus=0x0, threads=0x555556086fb0)
at util/evsel.c:2045
#3 0x000055555585d0db in evsel__open_per_thread (evsel=0x5555560951a0, threads=0x555556086fb0)
at util/evsel.c:2065
#4 0x00005555558ece64 in create_perf_stat_counter (evsel=0x5555560951a0,
config=0x555555c34700 <stat_config>, target=0x555555c2f1c0 <target>, cpu=0) at util/stat.c:590
#5 0x000055555578e927 in __run_perf_stat (argc=1, argv=0x7fffffffe4a0, run_idx=0)
at builtin-stat.c:833
#6 0x000055555578f3c6 in run_perf_stat (argc=1, argv=0x7fffffffe4a0, run_idx=0)
at builtin-stat.c:1048
#7 0x0000555555792ee5 in cmd_stat (argc=1, argv=0x7fffffffe4a0) at builtin-stat.c:2534
#8 0x0000555555835ed3 in run_builtin (p=0x555555c3f540 <commands+288>, argc=3,
argv=0x7fffffffe4a0) at perf.c:313
#9 0x0000555555836154 in handle_internal_command (argc=3, argv=0x7fffffffe4a0) at perf.c:365
#10 0x000055555583629f in run_argv (argcp=0x7fffffffe2ec, argv=0x7fffffffe2e0) at perf.c:409
#11 0x0000555555836692 in main (argc=3, argv=0x7fffffffe4a0) at perf.c:539
...
(gdb) c
Continuing.
Error:
The sys_perf_event_open() syscall returned with 22 (Invalid argument) for event (uncore_iio_0/event=0x83,umask=0x04,ch_mask=0xF,fc_mask=0x07/).
/bin/dmesg | grep -i perf may provide additional information.
Program received signal SIGSEGV, Segmentation fault.
0x00005555559b03ea in perf_evsel__close_fd_cpu (evsel=0x5555560951a0, cpu=1) at evsel.c:166
166 if (FD(evsel, cpu, thread) >= 0)
v3. fixes a bug in perf_evsel__run_ioctl where the sense of a branch was
backward.
Signed-off-by: Ian Rogers <irogers@google.com> Acked-by: Jiri Olsa <jolsa@redhat.com> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Stephane Eranian <eranian@google.com> Link: http://lore.kernel.org/lkml/20210918054440.2350466-1-irogers@google.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Michael Petlan [Mon, 19 Jul 2021 14:53:32 +0000 (16:53 +0200)]
perf machine: Initialize srcline string member in add_location struct
It's later supposed to be either a correct address or NULL. Without the
initialization, it may contain an undefined value which results in the
following segmentation fault:
# perf top --sort comm -g --ignore-callees=do_idle
terminates with:
#0 0x00007ffff56b7685 in __strlen_avx2 () from /lib64/libc.so.6
#1 0x00007ffff55e3802 in strdup () from /lib64/libc.so.6
#2 0x00005555558cb139 in hist_entry__init (callchain_size=<optimized out>, sample_self=true, template=0x7fffde7fb110, he=0x7fffd801c250) at util/hist.c:489
#3 hist_entry__new (template=template@entry=0x7fffde7fb110, sample_self=sample_self@entry=true) at util/hist.c:564
#4 0x00005555558cb4ba in hists__findnew_entry (hists=hists@entry=0x5555561d9e38, entry=entry@entry=0x7fffde7fb110, al=al@entry=0x7fffde7fb420,
sample_self=sample_self@entry=true) at util/hist.c:657
#5 0x00005555558cba1b in __hists__add_entry (hists=hists@entry=0x5555561d9e38, al=0x7fffde7fb420, sym_parent=<optimized out>, bi=bi@entry=0x0, mi=mi@entry=0x0,
sample=sample@entry=0x7fffde7fb4b0, sample_self=true, ops=0x0, block_info=0x0) at util/hist.c:288
#6 0x00005555558cbb70 in hists__add_entry (sample_self=true, sample=0x7fffde7fb4b0, mi=0x0, bi=0x0, sym_parent=<optimized out>, al=<optimized out>, hists=0x5555561d9e38)
at util/hist.c:1056
#7 iter_add_single_cumulative_entry (iter=0x7fffde7fb460, al=<optimized out>) at util/hist.c:1056
#8 0x00005555558cc8a4 in hist_entry_iter__add (iter=iter@entry=0x7fffde7fb460, al=al@entry=0x7fffde7fb420, max_stack_depth=<optimized out>, arg=arg@entry=0x7fffffff7db0)
at util/hist.c:1231
#9 0x00005555557cdc9a in perf_event__process_sample (machine=<optimized out>, sample=0x7fffde7fb4b0, evsel=<optimized out>, event=<optimized out>, tool=0x7fffffff7db0)
at builtin-top.c:842
#10 deliver_event (qe=<optimized out>, qevent=<optimized out>) at builtin-top.c:1202
#11 0x00005555558a9318 in do_flush (show_progress=false, oe=0x7fffffff80e0) at util/ordered-events.c:244
#12 __ordered_events__flush (oe=oe@entry=0x7fffffff80e0, how=how@entry=OE_FLUSH__TOP, timestamp=timestamp@entry=0) at util/ordered-events.c:323
#13 0x00005555558a9789 in __ordered_events__flush (timestamp=<optimized out>, how=<optimized out>, oe=<optimized out>) at util/ordered-events.c:339
#14 ordered_events__flush (how=OE_FLUSH__TOP, oe=0x7fffffff80e0) at util/ordered-events.c:341
#15 ordered_events__flush (oe=oe@entry=0x7fffffff80e0, how=how@entry=OE_FLUSH__TOP) at util/ordered-events.c:339
#16 0x00005555557cd631 in process_thread (arg=0x7fffffff7db0) at builtin-top.c:1114
#17 0x00007ffff7bb817a in start_thread () from /lib64/libpthread.so.0
#18 0x00007ffff5656dc3 in clone () from /lib64/libc.so.6
If you look at the frame #2, the code is:
488 if (he->srcline) {
489 he->srcline = strdup(he->srcline);
490 if (he->srcline == NULL)
491 goto err_rawdata;
492 }
If he->srcline is not NULL (it is not NULL if it is uninitialized rubbish),
it gets strdupped and strdupping a rubbish random string causes the problem.
Also, if you look at the commit 1fb7d06a509e, it adds the srcline property
into the struct, but not initializing it everywhere needed.
Committer notes:
Now I see, when using --ignore-callees=do_idle we end up here at line
2189 in add_callchain_ip():
2181 if (al.sym != NULL) {
2182 if (perf_hpp_list.parent && !*parent &&
2183 symbol__match_regex(al.sym, &parent_regex))
2184 *parent = al.sym;
2185 else if (have_ignore_callees && root_al &&
2186 symbol__match_regex(al.sym, &ignore_callees_regex)) {
2187 /* Treat this symbol as the root,
2188 forgetting its callees. */
2189 *root_al = al;
2190 callchain_cursor_reset(cursor);
2191 }
2192 }
And the al that doesn't have the ->srcline field initialized will be
copied to the root_al, so then, back to:
Adrian Hunter [Sat, 11 Sep 2021 13:30:53 +0000 (16:30 +0300)]
perf script: Fix ip display when type != attr->type
set_print_ip_opts() was not being called when type != attr->type
because there is not a one-to-one relationship between output types
and attr->type. That resulted in ip not printing.
The attr_type() function is removed, and the match of attr->type to
output type is corrected.
Example on ADL using taskset to select an atom cpu:
# perf record -e cpu_atom/cpu-cycles/ taskset 0x1000 uname
Linux
[ perf record: Woken up 1 times to write data ]
[ perf record: Captured and wrote 0.003 MB perf.data (7 samples) ]
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com> Reviewed-by: Kan Liang <kan.liang@linux.intel.com> Cc: Jin Yao <yao.jin@linux.intel.com> Cc: Jiri Olsa <jolsa@redhat.com> Link: http://lore.kernel.org/lkml/20210911133053.15682-1-adrian.hunter@intel.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Ravi Bangoria [Sat, 11 Sep 2021 04:38:53 +0000 (10:08 +0530)]
perf annotate: Fix fused instr logic for assembly functions
Some x86 microarchitectures fuse a subset of cmp/test/ALU instructions
with branch instructions, and thus perf annotate highlight such valid
pairs as fused.
When annotated with source, perf uses struct disasm_line to contain
either source or instruction line from objdump output. Usually, a C
statement generates multiple instructions which include such
cmp/test/ALU + branch instruction pairs. But in case of assembly
function, each individual assembly source line generate one
instruction.
The 'perf annotate' instruction fusion logic assumes the previous
disasm_line as the previous instruction line, which is wrong because,
for assembly function, previous disasm_line contains source line. And
thus perf fails to highlight valid fused instruction pairs for assembly
functions.
Fix it by searching backward until we find an instruction line and
consider that disasm_line as fused with current branch instruction.
Before:
│ cmpq %rcx, RIP+8(%rsp)
0.00 │ cmp %rcx,0x88(%rsp)
│ je .Lerror_bad_iret <--- Source line
0.14 │ ┌──je b4 <--- Instruction line
│ │movl %ecx, %eax
Reviewed-by: Jin Yao <yao.jin@linux.intel.com> Signed-off-by: Ravi Bangoria <ravi.bangoria@amd.com> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Kim Phillips <kim.phillips@amd.com> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Namhyung Kim <namhyung@kernel.org>
Link: https //lore.kernel.org/r/20210911043854.8373-1-ravi.bangoria@amd.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
The TGA boards were based on the DECchip 21030 PCI graphics accelerator
used mainly for alpha, and existed in a TURBOchannel (TC) version for
the DECstation (MIPS) workstations.
However, the config option for the TGA code is a bit confused, and says
depends on FB && (ALPHA || TC)
because people didn't really want to enable the option for random PCI
environments, so the "ALPHA" stands in for that case (while the TC case
is then the MIPS DECstation case).
So that config dependency is kind of a mixture of architecture and bus
choices. But it's incorrect, in that there were non-PCI-based alpha
hardware, and then the driver just causes warnings:
drivers/video/fbdev/tgafb.c:1532:13: error: ‘tgafb_unregister’ defined but not used [-Werror=unused-function]
1532 | static void tgafb_unregister(struct device *dev)
| ^~~~~~~~~~~~~~~~
drivers/video/fbdev/tgafb.c:1387:12: error: ‘tgafb_register’ defined but not used [-Werror=unused-function]
1387 | static int tgafb_register(struct device *dev)
| ^~~~~~~~~~~~~~
so let's make the config option dependencies a bit more explict:
depends on FB
depends on PCI || TC
depends on ALPHA || TC
where that first "FB" is the software configuration dependency, the
second "PCI || TC" is the hardware bus dependency, while that final
"ALPHA || TC" dependency is the "don't bother asking except for these
situations.
We could make that third case have "COMPILE_TEST" as an option, and mark
the register/unregister functions as __maybe_unused, but I'm not sure
it's really worth it.
The Jensen IO functions are overly copmplicated because some of the IO
addresses refer to special 'local IO' ports, and they get accessed
differently.
That then makes gcc not actually inline them, and since they were marked
"extern inline" when included through the regular <asm/io.h> path, and
then only marked "inline" when included from sys_jensen.c, you never
necessarily got a body for the IO functions at all.
The intent of the sys_jensen.c code is to actually get the non-inlined
copy generated, so remove the 'inline' from the magic macro that is
supposed to sort this all out.
Also, do not mix 'extern inline' functions (that may or may not be
inlined and will not generate a function body if they are not) with
'static inline' (that _will_ generate a function body when not inlined).
Because gcc will complain about this situation:
error: ‘jensen_bus_outb’ is static but used in inline function ‘jensen_outb’ which is not static
because gcc basically doesn't know whether to generate a body for that
static inline function or not for that call site.
So make all of these use that __EXTERN_INLINE marker. Gcc will
generally not inline these things on use, and then generate the function
body out-of-line in sys_jensen.c.
This makes the core IO functions build for the alpha Jensen config.
Not that the rest then builds, because it turns out Jensen also doesn't
enable PCI, which then makes other drievrs very unhappy, but that's a
separate issue.
Without CONFIG_PM enabled, the SET_RUNTIME_PM_OPS() macro ends up being
empty, and the only use of tegra_slink_runtime_{resume,suspend} goes
away, resulting in
drivers/spi/spi-tegra20-slink.c:1200:12: error: ‘tegra_slink_runtime_resume’ defined but not used [-Werror=unused-function]
1200 | static int tegra_slink_runtime_resume(struct device *dev)
| ^~~~~~~~~~~~~~~~~~~~~~~~~~
drivers/spi/spi-tegra20-slink.c:1188:12: error: ‘tegra_slink_runtime_suspend’ defined but not used [-Werror=unused-function]
1188 | static int tegra_slink_runtime_suspend(struct device *dev)
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~
mark the functions __maybe_unused to make the build happy.
This hits the alpha allmodconfig build (and others).
David Brazdil [Fri, 17 Sep 2021 13:14:23 +0000 (14:14 +0100)]
of: restricted dma: Fix condition for rmem init
of_dma_set_restricted_buffer fails to handle negative return values from
of_property_count_elems_of_size, e.g. when the property does not exist.
This results in an attempt to assign a non-existent reserved memory
region to the device and a warning being printed. Fix the condition to
take negative values into account.
Fixes: f3cfd136aef0 ("of: restricted dma: Don't fail device probe on rmem init failure") Cc: Will Deacon <will@kernel.org> Signed-off-by: David Brazdil <dbrazdil@google.com> Acked-by: Will Deacon <will@kernel.org> Link: https://lore.kernel.org/r/20210917131423.2760155-1-dbrazdil@google.com Signed-off-by: Rob Herring <robh@kernel.org>
Merge tag 'pm-5.15-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm
Pull power management fixes from Rafael Wysocki:
"These fix two cpufreq issues, one in the intel_pstate driver and one
in the core.
Specifics:
- Prevent intel_pstate from avoiding to use HWP, even if instructed
to do so via the kernel command line, when HWP has been enabled
already by the platform firmware (Doug Smythies).
- Prevent use-after-free from occurring in the schedutil cpufreq
governor on exit by fixing a core helper function that attempts to
access memory associated with a kobject after calling kobject_put()
on it (James Morse)"
* tag 'pm-5.15-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
cpufreq: schedutil: Destroy mutex before kobject_put() frees the memory
cpufreq: intel_pstate: Override parameters if HWP forced by BIOS
Merge tag 'dma-mapping-5.15-1' of git://git.infradead.org/users/hch/dma-mapping
Pull dma-mapping fixes from Christoph Hellwig:
- page align size in sparc32 arch_dma_alloc (Andreas Larsson)
- tone down a new dma-debug message (Hamza Mahfooz)
- fix the kerneldoc for dma_map_sg_attrs (me)
* tag 'dma-mapping-5.15-1' of git://git.infradead.org/users/hch/dma-mapping:
sparc32: page align size in arch_dma_alloc
dma-debug: prevent an error message from causing runtime problems
dma-mapping: fix the kerneldoc for dma_map_sg_attrs
Merge tag 'pci-v5.15-fixes-1' of git://git.kernel.org/pub/scm/linux/kernel/git/helgaas/pci
Pull PCI fixes from Bjorn Helgaas:
- Defer VPD sizing until we actually need the contents; fixes a
boot-time slowdown reported by Dave Jones (Bjorn Helgaas)
- Stop clobbering OF fwnodes when we look for an ACPI fwnode; fixes a
virtio-iommu boot regression (Jean-Philippe Brucker)
- Add AMD GPU multi-function power dependencies; fixes runtime power
management, including GPU resume and temp and fan sensor issues (Evan
Quan)
- Update VMD maintainer to Nirmal Patel (Jon Derrick)
* tag 'pci-v5.15-fixes-1' of git://git.kernel.org/pub/scm/linux/kernel/git/helgaas/pci:
MAINTAINERS: Add Nirmal Patel as VMD maintainer
PCI: Add AMD GPU multi-function power dependencies
PCI/ACPI: Don't reset a fwnode set by OF
PCI/VPD: Defer VPD sizing until first access
Merge tag 'iov_iter.3-5.15-2021-09-17' of git://git.kernel.dk/linux-block
Pull io_uring iov_iter retry fixes from Jens Axboe:
"This adds a helper to save/restore iov_iter state, and modifies
io_uring to use it.
After that is done, we can now kill the iter->truncated addition that
we added for this release. The io_uring change is being overly
cautious with the save/restore/advance, but better safe than sorry and
we can always improve that and reduce the overhead if it proves to be
of concern. The only case to be worried about in this regard is huge
IO, where iteration can take a while to iterate segments.
I spent some time writing test cases, and expanded the coverage quite
a bit from the last posting of this. liburing carries this regression
test case now:
which exercises all of this. It now also supports provided buffers,
and explicitly tests for end-of-file/device truncation as well.
On top of that, Pavel sanitized the IOPOLL retry path to follow the
exact same pattern as normal IO"
* tag 'iov_iter.3-5.15-2021-09-17' of git://git.kernel.dk/linux-block:
io_uring: move iopoll reissue into regular IO path
Revert "iov_iter: track truncated size"
io_uring: use iov_iter state save/restore helpers
iov_iter: add helper to save iov_iter state
Merge tag 'io_uring-5.15-2021-09-17' of git://git.kernel.dk/linux-block
Pull io_uring fixes from Jens Axboe:
"Mostly fixes for regressions in this cycle, but also a few fixes that
predate this release.
The odd one out is a tweak to the direct files added in this release,
where attempting to reuse a slot is allowed instead of needing an
explicit removal of that slot first. It's a considerable improvement
in usability to that API, hence I'm sending it for -rc2.
- io-wq race fix and cleanup (Hao)
- loop_rw_iter() type fix
- SQPOLL max worker race fix
- Allow poll arm for O_NONBLOCK files, fixing a case where it's
impossible to properly use io_uring if you cannot modify the file
flags
- Allow direct open to simply reuse a slot, instead of needing it
explicitly removed first (Pavel)
- Fix a case where we missed signal mask restoring in cqring_wait, if
we hit -EFAULT (Xiaoguang)"
* tag 'io_uring-5.15-2021-09-17' of git://git.kernel.dk/linux-block:
io_uring: allow retry for O_NONBLOCK if async is supported
io_uring: auto-removal for direct open/accept
io_uring: fix missing sigmask restore in io_cqring_wait()
io_uring: pin SQPOLL data before unlocking ring lock
io-wq: provide IO_WQ_* constants for IORING_REGISTER_IOWQ_MAX_WORKERS arg items
io-wq: fix potential race of acct->nr_workers
io-wq: code clean of io_wqe_create_worker()
io_uring: ensure symmetry in handling iter types in loop_rw_iter()
Merge tag 'block-5.15-2021-09-17' of git://git.kernel.dk/linux-block
Pull block fixes from Jens Axboe:
- NVMe pull request via Christoph:
- fix ANA state updates when a namespace is not present (Anton
Eidelman)
- nvmet: fix a width vs precision bug in
nvmet_subsys_attr_serial_show (Dan Carpenter)
- avoid race in shutdown namespace removal (Daniel Wagner)
- fix io_work priority inversion in nvme-tcp (Keith Busch)
- destroy cm id before destroy qp to avoid use after free (Ruozhu
Li)
* tag 'block-5.15-2021-09-17' of git://git.kernel.dk/linux-block:
blk-cgroup: fix UAF by grabbing blkcg lock before destroying blkg pd
blkcg: fix memory leak in blk_iolatency_init
nvme: remove the call to nvme_update_disk_info in nvme_ns_remove
block: flush the integrity workqueue in blk_integrity_unregister
block: check if a profile is actually registered in blk_integrity_unregister
nvme-tcp: fix io_work priority inversion
nvme-rdma: destroy cm id before destroy qp to avoid use after free
nvme-multipath: fix ANA state updates when a namespace is not present
nvme: avoid race in shutdown namespace removal
nvmet: fix a width vs precision bug in nvmet_subsys_attr_serial_show()
blk-mq: avoid to iterate over stale request
Merge tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux
Pull arm64 fixes and cleanups from Catalin Marinas:
- Fix the memset() size when re-initialising the SVE state.
- Mark __stack_chk_guard as __ro_after_init.
- Remove duplicate include.
* tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux:
arm64: Mark __stack_chk_guard as __ro_after_init
arm64/kernel: remove duplicate include in process.c
arm64/sve: Use correct size when reinitialising SVE state
Merge tag 'for-linus-5.15b-rc2-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip
Pull xen fixes from Juergen Gross:
- The first hunk of a Xen swiotlb fixup series fixing multiple minor
issues and doing some small cleanups
- Some further Xen related fixes avoiding WARN() splats when running as
Xen guests or dom0
- A Kconfig fix allowing the pvcalls frontend to be built as a module
* tag 'for-linus-5.15b-rc2-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip:
swiotlb-xen: drop DEFAULT_NSLABS
swiotlb-xen: arrange to have buffer info logged
swiotlb-xen: drop leftover __ref
swiotlb-xen: limit init retries
swiotlb-xen: suppress certain init retries
swiotlb-xen: maintain slab count properly
swiotlb-xen: fix late init retry
swiotlb-xen: avoid double free
xen/pvcalls: backend can be a module
xen: fix usage of pmd_populate in mremap for pv guests
xen: reset legacy rtc flag for PV domU
PM: base: power: don't try to use non-existing RTC for storing data
xen/balloon: use a kernel thread instead a workqueue
Merge tag 'drm-fixes-2021-09-17' of git://anongit.freedesktop.org/drm/drm
Pull drm fixes from Dave Airlie:
"Slightly busier than usual rc2, but mostly scattered amdgpu fixes,
some i915 and etnaviv resolves an MMU/runtime PM blowup.
amdgpu:
- UBSAN fix
- Powerplay table update fix
- Fix use after free in BO moves
- Debugfs init fixes
- vblank workqueue fixes for headless devices
- FPU fixes
- sysfs_emit fixes
- SMU updates for cyan skillfish
- Backlight fixes when DMCU is not initialized
- DP MST fixes
- HDCP compliance fix
- Link training fix
- Runtime pm fix
- Panel orientation fixes
- Display GPUVM fix for yellow carp
- Add missing license
amdkfd:
- Drop PCI atomics requirement if proper firmware is available
- Suspend/resume fixes for IOMMUv2 cases
radeon:
- AGP fix
i915:
- Propagate DP link training error returns
- Use max link params for eDP 1.3 and earlier
- Build warning fixes
- Gem selftest fixes
- Ensure wakeref is held before hardware access
etnaviv:
- MMU context vs runtime PM fix"
* tag 'drm-fixes-2021-09-17' of git://anongit.freedesktop.org/drm/drm: (44 commits)
drm/amdgpu/display: add a proper license to dc_link_dp.c
drm/amd/display: Fix white screen page fault for gpuvm
amd/display: enable panel orientation quirks
drm/amdgpu: Demote TMZ unsupported log message from warning to info
drm/amdgpu: Drop inline from amdgpu_ras_eeprom_max_record_count
drm/amd/pm: fix runpm hang when amdgpu loaded prior to sound driver
drm/radeon: pass drm dev radeon_agp_head_init directly
drm/amdgpu: move iommu_resume before ip init/resume
drm/amdgpu: add amdgpu_amdkfd_resume_iommu
drm/amdkfd: separate kfd_iommu_resume from kfd_resume
drm/amd/display: Link training retry fix for abort case
drm/amd/display: Fix unstable HPCP compliance on Chrome Barcelo
drm/amd/display: dsc mst 2 4K displays go dark with 2 lane HBR3
drm/amd/display: Get backlight from PWM if DMCU is not initialized
drm/amdkfd: make needs_pcie_atomics FW-version dependent
drm/amdgpu: add manual sclk/vddc setting support for cyan skilfish(v3)
drm/amdgpu: add some pptable funcs for cyan skilfish(v3)
drm/amdgpu: update SMU driver interface for cyan skilfish(v3)
drm/amdgpu: update SMU PPSMC for cyan skilfish
drm/amdgpu: fix sysfs_emit/sysfs_emit_at warnings(v2)
...
Dave Airlie [Thu, 16 Sep 2021 19:53:52 +0000 (05:53 +1000)]
Merge tag 'drm-intel-fixes-2021-09-16' of ssh://git.freedesktop.org/git/drm/drm-intel into drm-fixes
drm/i915 fixes for v5.15-rc2:
- Propagate DP link training error returns
- Use max link params for eDP 1.3 and earlier
- Build warning fixes
- Gem selftest fixes
- Ensure wakeref is held before hardware access
tx timeout and slot time are currently specified in units of HZ. On
Alpha, HZ is defined as 1024. When building alpha:allmodconfig, this
results in the following error message.
drivers/net/hamradio/6pack.c: In function 'sixpack_open':
drivers/net/hamradio/6pack.c:71:41: error:
unsigned conversion from 'int' to 'unsigned char'
changes value from '256' to '0'
In the 6PACK protocol, tx timeout is specified in units of 10 ms and
transmitted over the wire:
https://www.linux-ax25.org/wiki/6PACK
Defining a value dependent on HZ doesn't really make sense, and
presumably comes from the (very historical) situation where HZ was
originally 100.
Note that the SIXP_SLOTTIME use explicitly is about 10ms granularity:
Dave Airlie [Thu, 16 Sep 2021 19:30:56 +0000 (05:30 +1000)]
Merge branch 'etnaviv/fixes' of https://git.pengutronix.de/git/lst/linux into drm-fixes
Fixes a very annoying issue where the driver view of the MMU state gets
out of sync with the actual hardware state across a runtime PM cycle,
so we end up restarting the GPU with the wrong (potentially already
freed) MMU context. Hilarity ensues.
drm/rockchip: cdn-dp-core: Make cdn_dp_core_resume __maybe_unused
With the new static annotation, the compiler warns when the functions
are actually unused:
drivers/gpu/drm/rockchip/cdn-dp-core.c:1123:12: error: 'cdn_dp_resume' defined but not used [-Werror=unused-function]
1123 | static int cdn_dp_resume(struct device *dev)
| ^~~~~~~~~~~~~
Mark them __maybe_unused to suppress that warning as well.
[ Not so 'new' static annotations any more, and I removed the part of
the patch that added __maybe_unused to cdn_dp_suspend(), because it's
used by the shutdown/remove code.
So only the resume function ends up possibly unused if CONFIG_PM isn't
set - Linus ]
alpha: Declare virt_to_phys and virt_to_bus parameter as pointer to volatile
Some drivers pass a pointer to volatile data to virt_to_bus() and
virt_to_phys(), and that works fine. One exception is alpha. This
results in a number of compile errors such as
drivers/net/wan/lmc/lmc_main.c: In function 'lmc_softreset':
drivers/net/wan/lmc/lmc_main.c:1782:50: error:
passing argument 1 of 'virt_to_bus' discards 'volatile'
qualifier from pointer target type
drivers/atm/ambassador.c: In function 'do_loader_command':
drivers/atm/ambassador.c:1747:58: error:
passing argument 1 of 'virt_to_bus' discards 'volatile'
qualifier from pointer target type
Declare the parameter of virt_to_phys and virt_to_bus as pointer to
volatile to fix the problem.
3com 3c515: make it compile on 64-bit architectures
This driver isn't enabled most places because of the ISA config
dependency, but alpha still has it. And I think the 'Jensen' actually
did have an ISA slot.
However, it doesn't build cleanly, because the "Vortex bus master" code
just casts the skb->data pointer to 'int':
outl((int) (skb->data), ioaddr + Wn7_MasterAddr);
which is all kinds of broken. Even on a good old traditional PC/AT it
would be broken because the high bits will be random kernel address
bits, but presumably the hardware ignores those bits. I mean, it's ISA.
We're talking 16MB dma limits. The "good old days".
Make the build happy with this kind of craziness by using the proper
isa_virt_to_bus() handling that the full bus master code uses anyway
(the Vortex bus mastering is a limited special case).
Merge tag 'm68k-for-v5.15-tag2' of git://git.kernel.org/pub/scm/linux/kernel/git/geert/linux-m68k
Pull m68k fixes from Geert Uytterhoeven:
- Warning fixes to mitigate CONFIG_WERROR=y
* tag 'm68k-for-v5.15-tag2' of git://git.kernel.org/pub/scm/linux/kernel/git/geert/linux-m68k:
m68k: mvme: Remove overdue #warnings in RTC handling
m68k: Double cast io functions to unsigned long
Dan Li [Tue, 14 Sep 2021 09:44:02 +0000 (17:44 +0800)]
arm64: Mark __stack_chk_guard as __ro_after_init
__stack_chk_guard is setup once while init stage and never changed
after that.
Although the modification of this variable at runtime will usually
cause the kernel to crash (so does the attacker), it should be marked
as __ro_after_init, and it should not affect performance if it is
placed in the ro_after_init section.
Mark Brown [Thu, 9 Sep 2021 16:53:56 +0000 (17:53 +0100)]
arm64/sve: Use correct size when reinitialising SVE state
When we need a buffer for SVE register state we call sve_alloc() to make
sure that one is there. In order to avoid repeated allocations and frees
we keep the buffer around unless we change vector length and just memset()
it to ensure a clean register state. The function that deals with this
takes the task to operate on as an argument, however in the case where we
do a memset() we initialise using the SVE state size for the current task
rather than the task passed as an argument.
This is only an issue in the case where we are setting the register state
for a task via ptrace and the task being configured has a different vector
length to the task tracing it. In the case where the buffer is larger in
the traced process we will leak old state from the traced process to
itself, in the case where the buffer is smaller in the traced process we
will overflow the buffer and corrupt memory.
Simon Ser [Fri, 10 Sep 2021 15:37:41 +0000 (15:37 +0000)]
amd/display: enable panel orientation quirks
This patch allows panel orientation quirks from DRM core to be
used. They attach a DRM connector property "panel orientation"
which indicates in which direction the panel has been mounted.
Some machines have the internal screen mounted with a rotation.
Since the panel orientation quirks need the native mode from the
EDID, check for it in amdgpu_dm_connector_ddc_get_modes.
Signed-off-by: Simon Ser <contact@emersion.fr> Cc: Alex Deucher <alexander.deucher@amd.com> Cc: Harry Wentland <hwentlan@amd.com> Cc: Nicholas Kazlauskas <nicholas.kazlauskas@amd.com> Reviewed-by: Harry Wentland <harry.wentland@amd.com> Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Paul Menzel [Mon, 13 Sep 2021 08:34:11 +0000 (10:34 +0200)]
drm/amdgpu: Demote TMZ unsupported log message from warning to info
As the user cannot do anything about the unsupported Trusted Memory Zone
(TMZ) feature, do not warn about it, but make it informational, so
demote the log level from warning to info.
Signed-off-by: Paul Menzel <pmenzel@molgen.mpg.de> Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Michel Dänzer [Thu, 9 Sep 2021 16:56:28 +0000 (18:56 +0200)]
drm/amdgpu: Drop inline from amdgpu_ras_eeprom_max_record_count
This was unusual; normally, inline functions are declared static as
well, and defined in a header file if used by multiple compilation
units. The latter would be more involved in this case, so just drop
the inline declaration for now.
Fixes compile failure building for ppc64le on RHEL 8:
In file included from ../drivers/gpu/drm/amd/amdgpu/amdgpu_ras.h:32,
from ../drivers/gpu/drm/amd/amdgpu/amdgpu_ras.c:33:
../drivers/gpu/drm/amd/amdgpu/amdgpu_ras.c: In function ‘amdgpu_ras_recovery_init’:
../drivers/gpu/drm/amd/amdgpu/amdgpu_ras_eeprom.h:90:17: error: inlining failed in call
to ‘always_inline’ ‘amdgpu_ras_eeprom_max_record_count’: function body not available
90 | inline uint32_t amdgpu_ras_eeprom_max_record_count(void);
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
../drivers/gpu/drm/amd/amdgpu/amdgpu_ras.c:1985:34: note: called from here
1985 | max_eeprom_records_len = amdgpu_ras_eeprom_max_record_count();
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Fixes: c84d46707ebb "drm/amdgpu: validate bad page threshold in ras(v3)" Reviewed-by: Lyude Paul <lyude@redhat.com> Signed-off-by: Michel Dänzer <mdaenzer@redhat.com> Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Evan Quan [Thu, 9 Sep 2021 03:01:00 +0000 (11:01 +0800)]
drm/amd/pm: fix runpm hang when amdgpu loaded prior to sound driver
Current RUNPM mechanism relies on PMFW to master the timing for BACO
in/exit. And that needs cooperation from sound driver for dstate
change notification for function 1(audio). Otherwise(on sound driver
missing), BACO cannot be kicked in correctly and hang will be observed
on RUNPM exit.
By switching back to legacy message way on sound driver missing,
we are able to fix the runpm hang observed for the scenario below:
amdgpu driver loaded -> runpm suspend kicked -> sound driver loaded
Nirmoy Das [Mon, 13 Sep 2021 08:08:23 +0000 (10:08 +0200)]
drm/radeon: pass drm dev radeon_agp_head_init directly
Pass drm dev directly as rdev->ddev gets initialized later on
at radeon_device_init().
Bug: https://bugzilla.kernel.org/show_bug.cgi?id=214375 Signed-off-by: Nirmoy Das <nirmoy.das@amd.com> Reviewed-by: Christian König <christian.koenig@amd.com> Signed-off-by: Alex Deucher <alexander.deucher@amd.com> Cc: stable@vger.kernel.org
drm/amd/display: Link training retry fix for abort case
[Why]
If link training is aborted, it shall be retried if sink is present.
[How]
Check hpd status to find out whether sink is present or not. If sink is
present, then link training shall be tried again with same settings.
Otherwise, link training shall be aborted.
Reviewed-by: Jimmy Kizito <Jimmy.Kizito@amd.com> Acked-by: Mikita Lipski <mikita.lipski@amd.com> Signed-off-by: Meenakshikumar Somasundaram <meenakshikumar.somasundaram@amd.com> Tested-by: Daniel Wheeler <daniel.wheeler@amd.com> Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Qingqing Zhuo [Fri, 27 Aug 2021 10:58:38 +0000 (06:58 -0400)]
drm/amd/display: Fix unstable HPCP compliance on Chrome Barcelo
[Why]
Intermittently, there presents two occurrences of 0 stream
commits in a single HPD event. Current HDCP sequence does
not consider such scenerio, and will thus disable HDCP.
[How]
Add condition check to include stream remove and re-enable
case for HDCP enable.
Reviewed-by: Bhawanpreet Lakha <bhawanpreet.lakha@amd.com> Acked-by: Mikita Lipski <mikita.lipski@amd.com> Signed-off-by: Qingqing Zhuo <qingqing.zhuo@amd.com> Tested-by: Daniel Wheeler <daniel.wheeler@amd.com> Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Hersen Wu [Wed, 25 Aug 2021 20:27:47 +0000 (16:27 -0400)]
drm/amd/display: dsc mst 2 4K displays go dark with 2 lane HBR3
[Why]
call stack of amdgpu dsc mst pbn, slot num calculation is as below:
-compute_bpp_x16_from_target_bandwidth
-decide_dsc_target_bpp_x16
-setup_dsc_config
-dc_dsc_compute_bandwidth_range
-compute_mst_dsc_configs_for_link
-compute_mst_dsc_configs_for_state
from pbn -> dsc target bpp_x16
bpp_x16 is calulated by compute_bpp_x16_from_target_bandwidth.
Beside pixel clock and bpp, num_slices_h and bpp_increment_div
will also affect bpp_x16.
from dsc target bpp_x16 -> pbn
within dm_update_mst_vcpi_slots_for_dsc,
pbn = drm_dp_calc_pbn_mode(clock, bpp_x16, true);
bpp / 16 trunc digits after decimal point. This will cause calculation
delta. drm_dp_calc_pbn_mode does not have other informations,
like num_slices_h, bpp_increment_div. therefore, it does not do revese
calcuation properly from bpp_x16 to pbn.
pbn from drm_dp_calc_pbn_mode is less than pbn from
compute_mst_dsc_configs_for_state. This cause not enough mst slot
allocated to display. display could not visually light up.
[How]
pass pbn from compute_mst_dsc_configs_for_state to
dm_update_mst_vcpi_slots_for_dsc
Cc: stable@vger.kernel.org Reviewed-by: Scott Foster <Scott.Foster@amd.com> Acked-by: Mikita Lipski <mikita.lipski@amd.com> Signed-off-by: Hersen Wu <hersenwu@amd.com> Tested-by: Daniel Wheeler <daniel.wheeler@amd.com> Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Harry Wentland [Mon, 16 Aug 2021 19:57:12 +0000 (15:57 -0400)]
drm/amd/display: Get backlight from PWM if DMCU is not initialized
On Carrizo/Stoney systems we set backlight through panel_cntl, i.e.
directly via the PWM registers, if DMCU is not initialized. We
always read it back through ABM registers which leads to a
mismatch and forces atomic_commit to program the backlight
each time.
Instead make sure we use the same logic for backlight readback,
i.e. read it from panel_cntl if DMCU is not initialized.
We also need to remove some extraneous and incorrect calculations
at the end of dce_get_16_bit_backlight_from_pwm.
Bug: https://gitlab.freedesktop.org/drm/amd/-/issues/1666 Cc: stable@vger.kernel.org Reviewed-by: Josip Pavic <josip.pavic@amd.com> Acked-by: Mikita Lipski <mikita.lipski@amd.com> Signed-off-by: Harry Wentland <harry.wentland@amd.com> Tested-by: Daniel Wheeler <daniel.wheeler@amd.com> Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Felix Kuehling [Tue, 31 Aug 2021 21:42:15 +0000 (17:42 -0400)]
drm/amdkfd: make needs_pcie_atomics FW-version dependent
On some GPUs the PCIe atomic requirement for KFD depends on the MEC
firmware version. Add a firmware version check for this. The minimum
firmware version that works without atomics can be updated in the
device_info structure for each GPU type.
Move PCIe atomic detection from kgd2kfd_probe into kgd2kfd_device_init
because the MEC firmware is not loaded yet at the probe stage.
Signed-off-by: Felix Kuehling <Felix.Kuehling@amd.com> Reviewed-by: Guchun Chen <guchun.chen@amd.com> Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Lang Yu [Fri, 27 Aug 2021 07:20:51 +0000 (15:20 +0800)]
drm/amdgpu: add manual sclk/vddc setting support for cyan skilfish(v3)
Add manual sclk/vddc setting supoort via pp_od_clk_voltage sysfs
to maintain consistency with other asics. As cyan skillfish doesn't
support DPM, there is only a single frequency and voltage to adjust.
v2: maintain consistency and add command guide.
v3: adjust user settings storage and coding style.
Command guide:
echo vc point sclk vddc > pp_od_clk_voltage
"vc" - sclk voltage curve
"point" - must be 0
"sclk" - target value of sclk(MHz), should be in safe range
"vddc" - target value of vddc(mV), a 6.25(mV) stepping is
recommended and should be in safe range (the real
vddc is an approximation of target value)
echo c > pp_od_clk_voltage
"c" - commit the changes of sclk and vddc, only after
the commit command, the target values set by "vc"
command will take effect
echo r > pp_od_clk_voltage
"r" - reset sclk and vddc to default value, a subsequent
commit command is needed to take effect
Example:
1) Check default sclk and vddc
$ cat pp_od_clk_voltage
OD_SCLK:
0: 1800Mhz *
OD_VDDC:
0: 862mV *
OD_RANGE:
SCLK: 1000Mhz 2000Mhz
VDDC: 700mV 1129mV
2) Set sclk to 1500MHz and vddc to 700mV
$ echo vc 0 1500 700 > pp_od_clk_voltage
$ echo c > pp_od_clk_voltage
$ cat pp_od_clk_voltage
OD_SCLK:
0: 1500Mhz *
OD_VDDC:
0: 693mV *
OD_RANGE:
SCLK: 1000Mhz 2000Mhz
VDDC: 700mV 1129mV
3) Reset sclk and vddc to default
$ echo r > pp_od_clk_voltage
$ echo c > pp_od_clk_voltage
$ cat pp_od_clk_voltage
OD_SCLK:
0: 1800Mhz *
OD_VDDC:
0: 874mV *
OD_RANGE:
SCLK: 1000Mhz 2000Mhz
VDDC: 700mV 1129mV
NOTE:
We don't specify an explicit safe range, you can set any values
between min and max at your own risk. Enjoy!
Signed-off-by: Lang Yu <lang.yu@amd.com> Reviewed-by: Lijo Lazar <lijo.lazar@amd.com> Reviewed-by: Huang Rui <ray.huang@amd.com> Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
drm/amd/display: Add NULL checks for vblank workqueue
[Why]
If we're running a headless config with 0 links then the vblank
workqueue will be NULL - causing a NULL pointer exception during
any commit.
[How]
Guard access to the workqueue if it's NULL and don't queue or flush
work if it is.
Reported-by: Mike Lothian <mike@fireburn.co.uk> BugLink: https://gitlab.freedesktop.org/drm/amd/-/issues/1700 Fixes: 58aa1c50e5a231 ("drm/amd/display: Use vblank control events for PSR enable/disable") Signed-off-by: Nicholas Kazlauskas <nicholas.kazlauskas@amd.com> Reviewed-by: Harry Wentland <Harry.Wentland@amd.com> Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
David Thompson [Wed, 15 Sep 2021 18:08:48 +0000 (14:08 -0400)]
mlxbf_gige: clear valid_polarity upon open
The network interface managed by the mlxbf_gige driver can
get into a problem state where traffic does not flow.
In this state, the interface will be up and enabled, but
will stop processing received packets. This problem state
will happen if three specific conditions occur:
1) driver has received more than (N * RxRingSize) packets but
less than (N+1 * RxRingSize) packets, where N is an odd number
Note: the command "ethtool -g <interface>" will display the
current receive ring size, which currently defaults to 128
2) the driver's interface was disabled via "ifconfig oob_net0 down"
during the window described in #1.
3) the driver's interface is re-enabled via "ifconfig oob_net0 up"
This patch ensures that the driver's "valid_polarity" field is
cleared during the open() method so that it always matches the
receive polarity used by hardware. Without this fix, the driver
needs to be unloaded and reloaded to correct this problem state.
Fixes: f92e1869d74e ("Add Mellanox BlueField Gigabit Ethernet driver") Reviewed-by: Asmaa Mnebhi <asmaa@nvidia.com> Signed-off-by: David Thompson <davthompson@nvidia.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Paolo Abeni [Wed, 15 Sep 2021 17:19:07 +0000 (10:19 -0700)]
igc: fix tunnel offloading
Checking tunnel offloading, it turns out that offloading doesn't work
as expected. The following script allows to reproduce the issue.
Call it as `testscript DEVICE LOCALIP REMOTEIP NETMASK'
=== SNIP ===
if [ $# -ne 4 ]
then
echo "Usage $0 DEVICE LOCALIP REMOTEIP NETMASK"
exit 1
fi
DEVICE="$1"
LOCAL_ADDRESS="$2"
REMOTE_ADDRESS="$3"
NWMASK="$4"
echo "Driver: $(ethtool -i ${DEVICE} | awk '/^driver:/{print $2}') "
ethtool -k "${DEVICE}" | grep tx-udp
echo
echo "Set up NIC and tunnel..."
ip addr add "${LOCAL_ADDRESS}/${NWMASK}" dev "${DEVICE}"
ip link set "${DEVICE}" up
sleep 2
ip link add vxlan1 type vxlan id 42 \
remote "${REMOTE_ADDRESS}" \
local "${LOCAL_ADDRESS}" \
dstport 0 \
dev "${DEVICE}"
ip addr add fc00::1/64 dev vxlan1
ip link set vxlan1 up
sleep 2
rm -f vxlan.pcap
echo "Running tcpdump and iperf3..."
( nohup tcpdump -i any -w vxlan.pcap >/dev/null 2>&1 ) &
sleep 2
iperf3 -c fc00::2 >/dev/null
pkill tcpdump
echo
echo -n "Max. Paket Size: "
tcpdump -r vxlan.pcap -nnle 2>/dev/null \
| grep "${LOCAL_ADDRESS}.*> ${REMOTE_ADDRESS}.*OTV" \
| awk '{print $8}' | awk -F ':' '{print $1}' \
| sort -n | tail -1
echo
ip link del vxlan1
ip addr del ${LOCAL_ADDRESS}/${NWMASK} dev "${DEVICE}"
=== SNAP ===
The expected outcome is
Max. Paket Size: 64904
This is what you see on igb, the code igc has been taken from.
However, on igc the output is
Max. Paket Size: 1516
so the GSO aggregate packets are segmented by the kernel before calling
igc_xmit_frame. Inside the subsequent call to igc_tso, the check for
skb_is_gso(skb) fails and the function returns prematurely.
It turns out that this occurs because the feature flags aren't set
entirely correctly in igc_probe. In contrast to the original code
from igb_probe, igc_probe neglects to set the flags required to allow
tunnel offloading.
Setting the same flags as igb fixes the issue on igc.
Fixes: 34428dff3679 ("igc: Add GSO partial support") Signed-off-by: Paolo Abeni <pabeni@redhat.com> Tested-by: Corinna Vinschen <vinschen@redhat.com> Acked-by: Sasha Neftin <sasha.neftin@intel.com> Tested-by: Nechama Kraus <nechamax.kraus@linux.intel.com> Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Remove the assert from the callback priv lookup function since it does
not require RTNL lock and is already protected by flow_indr_block_lock.
This will avoid warnings from being emitted to dmesg if the driver
registers its callback after an ingress qdisc was created for a
netdevice.
The warnings started after the following patch was merged:
commit 74fc4f828769 ("net: Fix offloading indirect devices dependency on qdisc order creation")
Signed-off-by: Eli Cohen <elic@nvidia.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Lucas Stach [Fri, 20 Aug 2021 20:18:30 +0000 (22:18 +0200)]
drm/etnaviv: add missing MMU context put when reaping MMU mapping
When we forcefully evict a mapping from the the address space and thus the
MMU context, the MMU context is leaked, as the mapping no longer points to
it, so it doesn't get freed when the GEM object is destroyed. Add the
mssing context put to fix the leak.
Cc: stable@vger.kernel.org # 5.4 Signed-off-by: Lucas Stach <l.stach@pengutronix.de> Tested-by: Michael Walle <michael@walle.cc> Tested-by: Marek Vasut <marex@denx.de> Reviewed-by: Christian Gmeiner <christian.gmeiner@gmail.com>
Lucas Stach [Fri, 20 Aug 2021 20:18:29 +0000 (22:18 +0200)]
drm/etnaviv: reference MMU context when setting up hardware state
Move the refcount manipulation of the MMU context to the point where the
hardware state is programmed. At that point it is also known if a previous
MMU state is still there, or the state needs to be reprogrammed with a
potentially different context.
Cc: stable@vger.kernel.org # 5.4 Signed-off-by: Lucas Stach <l.stach@pengutronix.de> Tested-by: Michael Walle <michael@walle.cc> Tested-by: Marek Vasut <marex@denx.de> Reviewed-by: Christian Gmeiner <christian.gmeiner@gmail.com>
Lucas Stach [Fri, 20 Aug 2021 20:18:28 +0000 (22:18 +0200)]
drm/etnaviv: fix MMU context leak on GPU reset
After a reset the GPU is no longer using the MMU context and may be
restarted with a different context. While the mmu_state proeprly was
cleared, the context wasn't unreferenced, leading to a memory leak.
Cc: stable@vger.kernel.org # 5.4 Reported-by: Michael Walle <michael@walle.cc> Signed-off-by: Lucas Stach <l.stach@pengutronix.de> Tested-by: Michael Walle <michael@walle.cc> Tested-by: Marek Vasut <marex@denx.de> Reviewed-by: Christian Gmeiner <christian.gmeiner@gmail.com>
Lucas Stach [Fri, 20 Aug 2021 20:18:27 +0000 (22:18 +0200)]
drm/etnaviv: exec and MMU state is lost when resetting the GPU
When the GPU is reset both the current exec state, as well as all MMU
state is lost. Move the driver side state tracking into the reset function
to keep hardware and software state from diverging.
Cc: stable@vger.kernel.org # 5.4 Signed-off-by: Lucas Stach <l.stach@pengutronix.de> Tested-by: Michael Walle <michael@walle.cc> Tested-by: Marek Vasut <marex@denx.de> Reviewed-by: Christian Gmeiner <christian.gmeiner@gmail.com>
Lucas Stach [Fri, 20 Aug 2021 20:18:26 +0000 (22:18 +0200)]
drm/etnaviv: keep MMU context across runtime suspend/resume
The MMU state may be kept across a runtime suspend/resume cycle, as we
avoid a full hardware reset to keep the latency of the runtime PM small.
Don't pretend that the MMU state is lost in driver state. The MMU
context is pushed out when new HW jobs with a different context are
coming in. The only exception to this is when the GPU is unbound, in
which case we need to make sure to also free the last active context.
Cc: stable@vger.kernel.org # 5.4 Reported-by: Michael Walle <michael@walle.cc> Signed-off-by: Lucas Stach <l.stach@pengutronix.de> Tested-by: Michael Walle <michael@walle.cc> Tested-by: Marek Vasut <marex@denx.de> Reviewed-by: Christian Gmeiner <christian.gmeiner@gmail.com>
Lucas Stach [Fri, 20 Aug 2021 20:18:25 +0000 (22:18 +0200)]
drm/etnaviv: stop abusing mmu_context as FE running marker
While the DMA frontend can only be active when the MMU context is set, the
reverse isn't necessarily true, as the frontend can be stopped while the
MMU state is kept. Stop treating mmu_context being set as a indication that
the frontend is running and instead add a explicit property.
Cc: stable@vger.kernel.org # 5.4 Signed-off-by: Lucas Stach <l.stach@pengutronix.de> Tested-by: Michael Walle <michael@walle.cc> Tested-by: Marek Vasut <marex@denx.de> Reviewed-by: Christian Gmeiner <christian.gmeiner@gmail.com>
Lucas Stach [Fri, 20 Aug 2021 20:18:24 +0000 (22:18 +0200)]
drm/etnaviv: put submit prev MMU context when it exists
The prev context is the MMU context at the time of the job
queueing in hardware. As a job might be queued multiple times
due to recovery after a GPU hang, we need to make sure to put
the stale prev MMU context from a prior queuing, to avoid the
reference and thus the MMU context leaking.
Cc: stable@vger.kernel.org # 5.4 Signed-off-by: Lucas Stach <l.stach@pengutronix.de> Tested-by: Michael Walle <michael@walle.cc> Tested-by: Marek Vasut <marex@denx.de> Reviewed-by: Christian Gmeiner <christian.gmeiner@gmail.com>
Lucas Stach [Fri, 20 Aug 2021 20:18:23 +0000 (22:18 +0200)]
drm/etnaviv: return context from etnaviv_iommu_context_get
Being able to have the refcount manipulation in an assignment makes
it much easier to parse the code.
Cc: stable@vger.kernel.org # 5.4 Signed-off-by: Lucas Stach <l.stach@pengutronix.de> Tested-by: Michael Walle <michael@walle.cc> Tested-by: Marek Vasut <marex@denx.de> Reviewed-by: Christian Gmeiner <christian.gmeiner@gmail.com>
Merge tag 'hyperv-fixes-signed-20210915' of git://git.kernel.org/pub/scm/linux/kernel/git/hyperv/linux
Pull hyperv fixes from Wei Liu:
- Fix kernel crash caused by uio driver (Vitaly Kuznetsov)
- Remove on-stack cpumask from HV APIC code (Wei Liu)
* tag 'hyperv-fixes-signed-20210915' of git://git.kernel.org/pub/scm/linux/kernel/git/hyperv/linux:
x86/hyperv: remove on-stack cpumask from hv_send_ipi_mask_allbutself
asm-generic/hyperv: provide cpumask_to_vpset_noself
Drivers: hv: vmbus: Fix kernel crash upon unbinding a device from uio_hv_generic driver
Merge tag 'rtc-5.15-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/abelloni/linux
Pull RTC fix from Alexandre Belloni:
"Fix a locking issue in the cmos rtc driver"
* tag 'rtc-5.15-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/abelloni/linux:
rtc: cmos: Disable irq around direct invocation of cmos_interrupt()
Vladimir Oltean [Tue, 14 Sep 2021 13:47:26 +0000 (16:47 +0300)]
net: dsa: flush switchdev workqueue before tearing down CPU/DSA ports
Sometimes when unbinding the mv88e6xxx driver on Turris MOX, these error
messages appear:
mv88e6085 d0032004.mdio-mii:12: port 1 failed to delete be:79:b4:9e:9e:96 vid 1 from fdb: -2
mv88e6085 d0032004.mdio-mii:12: port 1 failed to delete be:79:b4:9e:9e:96 vid 0 from fdb: -2
mv88e6085 d0032004.mdio-mii:12: port 1 failed to delete d8:58:d7:00:ca:6d vid 100 from fdb: -2
mv88e6085 d0032004.mdio-mii:12: port 1 failed to delete d8:58:d7:00:ca:6d vid 1 from fdb: -2
mv88e6085 d0032004.mdio-mii:12: port 1 failed to delete d8:58:d7:00:ca:6d vid 0 from fdb: -2
(and similarly for other ports)
What happens is that DSA has a policy "even if there are bugs, let's at
least not leak memory" and dsa_port_teardown() clears the dp->fdbs and
dp->mdbs lists, which are supposed to be empty.
But deleting that cleanup code, the warnings go away.
=> the FDB and MDB lists (used for refcounting on shared ports, aka CPU
and DSA ports) will eventually be empty, but are not empty by the time
we tear down those ports. Aka we are deleting them too soon.
The addresses that DSA complains about are host-trapped addresses: the
local addresses of the ports, and the MAC address of the bridge device.
The problem is that offloading those entries happens from a deferred
work item scheduled by the SWITCHDEV_FDB_DEL_TO_DEVICE handler, and this
races with the teardown of the CPU and DSA ports where the refcounting
is kept.
In fact, not only it races, but fundamentally speaking, if we iterate
through the port list linearly, we might end up tearing down the shared
ports even before we delete a DSA user port which has a bridge upper.
So as it turns out, we need to first tear down the user ports (and the
unused ones, for no better place of doing that), then the shared ports
(the CPU and DSA ports). In between, we need to ensure that all work
items scheduled by our switchdev handlers (which only run for user
ports, hence the reason why we tear them down first) have finished.
Fixes: 161ca59d39e9 ("net: dsa: reference count the MDB entries at the cross-chip notifier level") Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com> Reviewed-by: Florian Fainelli <f.fainelli@gmail.com> Link: https://lore.kernel.org/r/20210914134726.2305133-1-vladimir.oltean@nxp.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Vladimir Oltean [Tue, 14 Sep 2021 14:05:15 +0000 (17:05 +0300)]
Revert "net: phy: Uniform PHY driver access"
This reverts commit 3ac8eed62596387214869319379c1fcba264d8c6, which did
more than it said on the box, and not only it replaced to_phy_driver
with phydev->drv, but it also removed the "!drv" check, without actually
explaining why that is fine.
That patch in fact breaks suspend/resume on any system which has PHY
devices with no drivers bound.
The stack trace is:
Unable to handle kernel NULL pointer dereference at virtual address 00000000000000e8
pc : mdio_bus_phy_suspend+0xd8/0xec
lr : dpm_run_callback+0x38/0x90
Call trace:
mdio_bus_phy_suspend+0xd8/0xec
dpm_run_callback+0x38/0x90
__device_suspend+0x108/0x3cc
dpm_suspend+0x140/0x210
dpm_suspend_start+0x7c/0xa0
suspend_devices_and_enter+0x13c/0x540
pm_suspend+0x2a4/0x330
Examples why that assumption is not fine:
- There is an MDIO bus with a PHY device that doesn't have a specific
PHY driver loaded, because mdiobus_register() automatically creates a
PHY device for it but there is no specific PHY driver in the system.
Normally under those circumstances, the generic PHY driver will be
bound lazily to it (at phy_attach_direct time). But some Ethernet
drivers attach to their PHY at .ndo_open time. Until then it, the
to-be-driven-by-genphy PHY device will not have a driver. The blamed
patch amounts to saying "you need to open all net devices before the
system can suspend, to avoid the NULL pointer dereference".
- There is any raw MDIO device which has 'plausible' values in the PHY
ID registers 2 and 3, which is located on an MDIO bus whose driver
does not set bus->phy_mask = ~0 (which prevents auto-scanning of PHY
devices). An example could be a MAC's internal MDIO bus with PCS
devices on it, for serial links such as SGMII. PHY devices will get
created for those PCSes too, due to that MDIO bus auto-scanning, and
although those PHY devices are not used, they do not bother anybody
either. PCS devices are usually managed in Linux as raw MDIO devices.
Nonetheless, they do not have a PHY driver, nor does anybody attempt
to connect to them (because they are not a PHY), and therefore this
patch breaks that.
The goal itself of the patch is questionable, so I am going for a
straight revert. to_phy_driver does not seem to have a need to be
replaced by phydev->drv, in fact that might even trigger code paths
which were not given too deep of a thought.
For instance:
phy_probe populates phydev->drv at the beginning, but does not clean it
up on any error (including EPROBE_DEFER). So if the phydev driver
requests probe deferral, phydev->drv will remain populated despite there
being no driver bound.
If a system suspend starts in between the initial probe deferral request
and the subsequent probe retry, we will be calling the phydev->drv->suspend
method, but _before_ any phydev->drv->probe call has succeeded.
That is to say, if the phydev->drv is allocating any driver-private data
structure in ->probe, it pretty much expects that data structure to be
available in ->suspend. But it may not. That is a pretty insane
environment to present to PHY drivers.
In the code structure before the blamed patch, mdio_bus_phy_may_suspend
would just say "no, don't suspend" to any PHY device which does not have
a driver pointer _in_the_device_structure_ (not the phydev->drv). That
would essentially ensure that ->suspend will never get called for a
device that has not yet successfully completed probe. This is the code
structure the patch is returning to, via the revert.
Vladimir Oltean [Tue, 14 Sep 2021 13:43:31 +0000 (16:43 +0300)]
net: dsa: destroy the phylink instance on any error in dsa_slave_phy_setup
DSA supports connecting to a phy-handle, and has a fallback to a non-OF
based method of connecting to an internal PHY on the switch's own MDIO
bus, if no phy-handle and no fixed-link nodes were present.
The -ENODEV error code from the first attempt (phylink_of_phy_connect)
is what triggers the second attempt (phylink_connect_phy).
However, when the first attempt returns a different error code than
-ENODEV, this results in an unbalance of calls to phylink_create and
phylink_destroy by the time we exit the function. The phylink instance
has leaked.
There are many other error codes that can be returned by
phylink_of_phy_connect. For example, phylink_validate returns -EINVAL.
So this is a practical issue too.
Fixes: aab9c4067d23 ("net: dsa: Plug in PHYLINK support") Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com> Reviewed-by: Florian Fainelli <f.fainelli@gmail.com> Reviewed-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk> Link: https://lore.kernel.org/r/20210914134331.2303380-1-vladimir.oltean@nxp.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Evan Quan [Fri, 3 Sep 2021 06:33:11 +0000 (14:33 +0800)]
PCI: Add AMD GPU multi-function power dependencies
Some AMD GPUs have built-in USB xHCI and USB Type-C UCSI controllers with
power dependencies between the GPU and the other functions as in 6d2e369f0d4c ("PCI: Add NVIDIA GPU multi-function power dependencies").
Add device link support for the AMD integrated USB xHCI and USB Type-C UCSI
controllers.
Without this, runtime power management, including GPU resume and temp and
fan sensors don't work correctly.
Commit 375553a93201 ("PCI: Setup ACPI fwnode early and at the same time
with OF") added a call to pci_set_acpi_fwnode() in pci_setup_device(),
which unconditionally clears any fwnode previously set by
pci_set_of_node().
pci_set_acpi_fwnode() looks for ACPI_COMPANION(), which only returns the
existing fwnode if it was set by ACPI_COMPANION_SET(). If it was set by
OF instead, ACPI_COMPANION() returns NULL and pci_set_acpi_fwnode()
accidentally clears the fwnode. To fix this, look for any fwnode instead
of just ACPI companions.
Fixes a virtio-iommu boot regression in v5.15-rc1.
Fixes: 375553a93201 ("PCI: Setup ACPI fwnode early and at the same time with OF") Link: https://lore.kernel.org/r/20210913172358.1775381-1-jean-philippe@linaro.org Signed-off-by: Jean-Philippe Brucker <jean-philippe@linaro.org> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> Acked-by: Rob Herring <robh@kernel.org> Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
7bac54497c3e ("PCI/VPD: Determine VPD size in pci_vpd_init()") reads VPD at
enumeration-time to find the size. But this is quite slow, and we don't
need the size until we actually need data from VPD. Dave reported a boot
slowdown of more than two minutes [1].
Defer the VPD sizing until a driver or the user (via sysfs) requests
information from VPD.
If devices are quirked because VPD is known not to work, don't bother even
looking for the VPD capability. The VPD will not be accessible at all.
The qnx4 directory entries are 64-byte blocks that have different
contents depending on the a status byte that is in the last byte of the
block.
In particular, a directory entry can be either a "link info" entry with
a 48-byte name and pointers to the real inode information, or an "inode
entry" with a smaller 16-byte name and the full inode information.
But the code was written to always just treat the directory name as if
it was part of that "inode entry", and just extend the name to the
longer case if the status byte said it was a link entry.
That work just fine and gives the right results, but now that gcc is
tracking data structure accesses much more, the code can trigger a
compiler error about using up to 48 bytes (the long name) in a structure
that only has that shorter name in it:
fs/qnx4/dir.c: In function ‘qnx4_readdir’:
fs/qnx4/dir.c:51:32: error: ‘strnlen’ specified bound 48 exceeds source size 16 [-Werror=stringop-overread]
51 | size = strnlen(de->di_fname, size);
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~
In file included from fs/qnx4/qnx4.h:3,
from fs/qnx4/dir.c:16:
include/uapi/linux/qnx4_fs.h:45:25: note: source object declared here
45 | char di_fname[QNX4_SHORT_NAME_MAX];
| ^~~~~~~~
which is because the source code doesn't really make this whole "one of
two different types" explicit.
Fix this by introducing a very explicit union of the two types, and
basically explaining to the compiler what is really going on.
The sparc mdesc code does pointer games with 'struct mdesc_hdr', but
didn't describe to the compiler how that header is then followed by the
data that the header describes.
As a result, gcc is now unhappy since it does stricter pointer range
tracking, and doesn't understand about how these things work. This
results in various errors like:
arch/sparc/kernel/mdesc.c: In function ‘mdesc_node_by_name’:
arch/sparc/kernel/mdesc.c:647:22: error: ‘strcmp’ reading 1 or more bytes from a region of size 0 [-Werror=stringop-overread]
647 | if (!strcmp(names + ep[ret].name_offset, name))
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
which are easily avoided by just describing 'struct mdesc_hdr' better,
and making the node_block() helper function look into that unsized
data[] that follows the header.
This makes the sparc64 build happy again at least for my cross-compiler
version (gcc version 11.2.1).
Merge branch 'absolute-pointer' (patches from Guenter)
Merge absolute_pointer macro series from Guenter Roeck:
"Kernel test builds currently fail for several architectures with error
messages such as the following.
drivers/net/ethernet/i825xx/82596.c: In function 'i82596_probe':
arch/m68k/include/asm/string.h:72:25: error:
'__builtin_memcpy' reading 6 bytes from a region of size 0
[-Werror=stringop-overread]
Such warnings may be reported by gcc 11.x for string and memory
operations on fixed addresses if gcc's builtin functions are used for
those operations.
This series introduces absolute_pointer() to fix the problem.
absolute_pointer() disassociates a pointer from its originating symbol
type and context, and thus prevents gcc from making assumptions about
pointers passed to memory operations"
* emailed patches from Guenter Roeck <linux@roeck-us.net>:
alpha: Use absolute_pointer to define COMMAND_LINE
alpha: Move setup.h out of uapi
net: i825xx: Use absolute_pointer for memcpy from fixed memory location
compiler.h: Introduce absolute_pointer macro
net: i825xx: Use absolute_pointer for memcpy from fixed memory location
gcc 11.x reports the following compiler warning/error.
drivers/net/ethernet/i825xx/82596.c: In function 'i82596_probe':
arch/m68k/include/asm/string.h:72:25: error:
'__builtin_memcpy' reading 6 bytes from a region of size 0 [-Werror=stringop-overread]
Use absolute_pointer() to work around the problem.
absolute_pointer() disassociates a pointer from its originating symbol
type and context. Use it to prevent compiler warnings/errors such as
drivers/net/ethernet/i825xx/82596.c: In function 'i82596_probe':
arch/m68k/include/asm/string.h:72:25: error:
'__builtin_memcpy' reading 6 bytes from a region of size 0 [-Werror=stringop-overread]
Such warnings may be reported by gcc 11.x for string and memory
operations on fixed addresses.
Li Jinlin [Tue, 14 Sep 2021 04:26:05 +0000 (12:26 +0800)]
blk-cgroup: fix UAF by grabbing blkcg lock before destroying blkg pd
KASAN reports a use-after-free report when doing fuzz test:
[693354.104835] ==================================================================
[693354.105094] BUG: KASAN: use-after-free in bfq_io_set_weight_legacy+0xd3/0x160
[693354.105336] Read of size 4 at addr ffff888be0a35664 by task sh/1453338
[693354.108511] Memory state around the buggy address:
[693354.108671] ffff888be0a35500: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
[693354.116396] ffff888be0a35580: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
[693354.124473] >ffff888be0a35600: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
[693354.132421] ^
[693354.140284] ffff888be0a35680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
[693354.147912] ffff888be0a35700: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
[693354.155281] ==================================================================
blkgs are protected by both queue and blkcg locks and holding
either should stabilize them. However, the path of destroying
blkg policy data is only protected by queue lock in
blkcg_activate_policy()/blkcg_deactivate_policy(). Other tasks
can get the blkg policy data before the blkg policy data is
destroyed, and use it after destroyed, which will result in a
use-after-free.
Once blk_throtl_init() queue init failed, blkcg_iolatency_exit() will
not be invoked for cleanup. That leads a memory leak. Swap the
blk_throtl_init() and blk_iolatency_init() calls can solve this.
tools/bootconfig: Define memblock_free_ptr() to fix build error
The lib/bootconfig.c file is shared with the 'bootconfig' tooling, and
as a result, the changes incommit 77e02cf57b6c ("memblock: introduce
saner 'memblock_free_ptr()' interface") need to also be reflected in the
tooling header file.
So define the new memblock_free_ptr() wrapper, and remove unused __pa()
and memblock_free().
Pavel Begunkov [Wed, 15 Sep 2021 10:00:05 +0000 (11:00 +0100)]
io_uring: move iopoll reissue into regular IO path
230d50d448acb ("io_uring: move reissue into regular IO path")
made non-IOPOLL I/O to not retry from ki_complete handler. Follow it
steps and do the same for IOPOLL. Same problems, same implementation,
same -EAGAIN assumptions.
Get rid of the need to do re-expand and revert on an iterator when we
encounter a short IO, or failure that warrants a retry. Use the new
state save/restore helpers instead.
We keep the iov_iter_state persistent across retries, if we need to
restart the read or write operation. If there's a pending retry, the
operation will always exit with the state correctly saved.
Merge tag 'nvme-5.15-2021-09-15' of git://git.infradead.org/nvme into block-5.15
Pull NVMe fixes from Christoph:
"nvme fixes for Linux 5.15
- fix ANA state updates when a namespace is not present (Anton Eidelman)
- nvmet: fix a width vs precision bug in nvmet_subsys_attr_serial_show
(Dan Carpenter)
- avoid race in shutdown namespace removal (Daniel Wagner)
- fix io_work priority inversion in nvme-tcp (Keith Busch)
- destroy cm id before destroy qp to avoid use after free (Ruozhu Li)"
* tag 'nvme-5.15-2021-09-15' of git://git.infradead.org/nvme:
nvme-tcp: fix io_work priority inversion
nvme-rdma: destroy cm id before destroy qp to avoid use after free
nvme-multipath: fix ANA state updates when a namespace is not present
nvme: avoid race in shutdown namespace removal
nvmet: fix a width vs precision bug in nvmet_subsys_attr_serial_show()
Some PHYs pointed to by "phy-handle" will never bind to a driver until a
consumer attaches to it. And when the consumer attaches to it, they get
forcefully bound to a generic PHY driver. In such cases, parsing the
phy-handle property and creating a device link will prevent the consumer
from ever probing. We don't want that. So revert support for
"phy-handle" property until we come up with a better mechanism for
binding PHYs to generic drivers before a consumer tries to attach to it.
s390 is the only architecture which allows to set the
-mwarn-dynamicstack compile option. This however will also always
generate a warning with system call stack randomization, which uses
alloca to generate some random sized stack frame.
On the other hand Linus just enabled "-Werror" by default with commit 3fe617ccafd6 ("Enable '-Werror' by default for all kernel builds"),
which means compiles will always fail by default.
So instead of playing once again whack-a-mole for something which is
s390 specific, simply remove this option.
drivers/s390/crypto/ap_bus.c:216: warning:
bad line:
drivers/s390/crypto/ap_bus.c:444:
warning: Function parameter or member 'floating' not described in 'ap_interrupt_handler'
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