From f3bd35430de5a9a1b10e1ae9c489e0a68a8c850a Mon Sep 17 00:00:00 2001 From: Sven Schnelle Date: Fri, 6 Mar 2020 13:19:34 +0100 Subject: [PATCH] s390/ptrace: pass invalid syscall numbers to tracing tracing expects to see invalid syscalls, so pass it through. The syscall path in entry.S checks the syscall number before looking up the handler, so it is still safe. Signed-off-by: Sven Schnelle Signed-off-by: Vasily Gorbik --- arch/s390/kernel/entry.S | 2 +- arch/s390/kernel/ptrace.c | 6 ++---- 2 files changed, 3 insertions(+), 5 deletions(-) diff --git a/arch/s390/kernel/entry.S b/arch/s390/kernel/entry.S index 50ff6dd0f9957..496f74d984732 100644 --- a/arch/s390/kernel/entry.S +++ b/arch/s390/kernel/entry.S @@ -401,9 +401,9 @@ ENTRY(system_call) jnz .Lsysc_nr_ok # svc 0: system call number in %r1 llgfr %r1,%r1 # clear high word in r1 + sth %r1,__PT_INT_CODE+2(%r11) cghi %r1,NR_syscalls jnl .Lsysc_nr_ok - sth %r1,__PT_INT_CODE+2(%r11) slag %r8,%r1,3 .Lsysc_nr_ok: xc __SF_BACKCHAIN(8,%r15),__SF_BACKCHAIN(%r15) diff --git a/arch/s390/kernel/ptrace.c b/arch/s390/kernel/ptrace.c index ceb8105a8086f..1fdbb2d19477b 100644 --- a/arch/s390/kernel/ptrace.c +++ b/arch/s390/kernel/ptrace.c @@ -847,11 +847,9 @@ asmlinkage long do_syscall_trace_enter(struct pt_regs *regs) * call number to gprs[2]. */ if (test_thread_flag(TIF_SYSCALL_TRACE) && - (tracehook_report_syscall_entry(regs) || - regs->gprs[2] >= NR_syscalls)) { + tracehook_report_syscall_entry(regs)) { /* - * Tracing decided this syscall should not happen or the - * debugger stored an invalid system call number. Skip + * Tracing decided this syscall should not happen. Skip * the system call and the system call restart handling. */ goto skip; -- 2.39.5