drm/i915/gvt: Fix unsafe locking caused by spin_unlock_bh
The caller of shadow_context_status_change may disable irqs. So it is not
safe to use spin_unlock_bh in such context. Let's switch to irqsave version
for safety.
------------[ cut here ]------------
WARNING: CPU: 2 PID: 4504 at kernel/softirq.c:161 __local_bh_enable_ip+0x46/0x60
[ 168.797710] Hardware name: Dell Inc. OptiPlex 7040/0Y7WYT, BIOS 1.2.8 01/26/2016
[ 168.797712] task:
ffff8c693d22db80 task.stack:
ffffb51b482bc000
[ 168.797718] RIP: 0010:__local_bh_enable_ip+0x46/0x60
[ 168.797721] RSP: 0018:
ffffb51b482bfa10 EFLAGS:
00010046
[ 168.797724] RAX:
0000000000000046 RBX:
ffff8c6900278000 RCX:
00000000ffffffff
[ 168.797726] RDX:
0000000000000001 RSI:
0000000000000200 RDI:
ffffffffc06a0330
[ 168.797728] RBP:
ffffb51b482bfa10 R08:
0000000000000000 R09:
ffff8c690027cb90
[ 168.797730] R10:
ffffb51b482bfa40 R11:
00000004072f0001 R12:
0000000000000000
[ 168.797732] R13:
0000000000000000 R14:
ffff8c690027ca9c R15:
0000000000000000
[ 168.797735] FS:
00007ff187c56700(0000) GS:
ffff8c6959d00000(0000) knlGS:
0000000000000000
[ 168.797738] CS: 0010 DS: 0000 ES: 0000 CR0:
0000000080050033
[ 168.797740] CR2:
0000562bc0c3991f CR3:
0000000430614006 CR4:
00000000003606e0
[ 168.797742] DR0:
0000000000000000 DR1:
0000000000000000 DR2:
0000000000000000
[ 168.797744] DR3:
0000000000000000 DR6:
00000000fffe0ff0 DR7:
0000000000000400
[ 168.797745] Call Trace:
[ 168.797755] _raw_spin_unlock_bh+0x1e/0x20
[ 168.797826] shadow_context_status_change+0x120/0x1e0 [i915]
[ 168.797831] notifier_call_chain+0x4a/0x70
[ 168.797834] atomic_notifier_call_chain+0x1a/0x20
[ 168.797896] execlists_cancel_port_requests+0x4f/0x80 [i915]
[ 168.797956] reset_common_ring+0x30/0x100 [i915]
[ 168.798007] i915_gem_reset_engine+0x114/0x330 [i915]
[ 168.798060] ? i915_gem_retire_requests+0x75/0x180 [i915]
[ 168.798111] i915_gem_reset+0x3e/0xb0 [i915]
[ 168.798149] i915_reset+0x10b/0x1c0 [i915]
[ 168.798187] i915_reset_device+0x209/0x220 [i915]
[ 168.798225] ? gen8_gt_irq_ack+0x170/0x170 [i915]
[ 168.798229] ? __queue_work+0x430/0x430
[ 168.798270] i915_handle_error+0x285/0x420 [i915]
[ 168.798275] ? mntput+0x24/0x40
[ 168.798281] ? terminate_walk+0x8e/0xf0
[ 168.798328] i915_wedged_set+0x84/0xc0 [i915]
[ 168.798333] simple_attr_write+0xab/0xc0
[ 168.798337] full_proxy_write+0x54/0x90
[ 168.798343] __vfs_write+0x37/0x170
[ 168.798349] ? common_file_perm+0x4c/0x100
[ 168.798355] ? apparmor_file_permission+0x1a/0x20
[ 168.798361] ? security_file_permission+0x3b/0xc0
[ 168.798365] vfs_write+0xb8/0x1b0
[ 168.798370] SyS_write+0x55/0xc0
[ 168.798376] entry_SYSCALL_64_fastpath+0x1e/0xa9
Fixes: 0e86cc9 ("drm/i915/gvt: implement per-vm mmio switching optimization")
Signed-off-by: Changbin Du <changbin.du@intel.com>
Signed-off-by: Zhenyu Wang <zhenyuw@linux.intel.com>
projects / kernel.git / commit