Messages in this thread | ![/](/images/icornerl.gif) | | From | Brian Gerst <> | Date | Sun, 30 Aug 2020 00:40:42 -0400 | Subject | Re: ptrace_syscall_32 is failing |
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On Sat, Aug 29, 2020 at 12:52 PM Andy Lutomirski <luto@kernel.org> wrote: > > Seems to be a recent regression, maybe related to entry/exit work changes. > > # ./tools/testing/selftests/x86/ptrace_syscall_32 > [RUN] Check int80 return regs > [OK] getpid() preserves regs > [OK] kill(getpid(), SIGUSR1) preserves regs > [RUN] Check AT_SYSINFO return regs > [OK] getpid() preserves regs > [OK] kill(getpid(), SIGUSR1) preserves regs > [RUN] ptrace-induced syscall restart > Child will make one syscall > [RUN] SYSEMU > [FAIL] Initial args are wrong (nr=224, args=10 11 12 13 14 4289172732) > [RUN] Restart the syscall (ip = 0xf7f3b549) > [OK] Restarted nr and args are correct > [RUN] Change nr and args and restart the syscall (ip = 0xf7f3b549) > [OK] Replacement nr and args are correct > [OK] Child exited cleanly > [RUN] kernel syscall restart under ptrace > Child will take a nap until signaled > [RUN] SYSCALL > [FAIL] Initial args are wrong (nr=29, args=0 0 0 0 0 4289172732) > [RUN] SYSCALL > [OK] Args after SIGUSR1 are correct (ax = -514) > [OK] Child got SIGUSR1 > [RUN] Step again > [OK] pause(2) restarted correctly
Bisected to commit 0b085e68f407 ("x86/entry: Consolidate 32/64 bit syscall entry"). It looks like it is because syscall_enter_from_user_mode() is called before reading the 6th argument from the user stack.
-- Brian Gerst
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