From 2c1dde8a69a3a7d64425a6de0add6e289a5a402f Mon Sep 17 00:00:00 2001 From: Shrikanth Hegde Date: Fri, 28 Aug 2026 11:08:11 +0530 Subject: [PATCH] powerpc/entry: Clear TIF_SYSCALL_RET before syscall error return Shivaprasad reported a boot failure due to userspace processes crash on abort() from libc.so.6. It was bisected to merge request commit '3424d8c18a7d ("Merge tag 'core-entry-2026-08-17' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip")' Upon checking the merge, when syscall_enter_from_user_mode_randomize_stack fails, which could happen when a tracer like seccomp or ptrace intercepts and skips the syscall, the code returns to userspace immediately without clearing the intermediate flag which was set. When the next syscall is made, it immediately aborts the valid syscall since the flag is still set. Hence clear the flag on occurrence of first failure. Reported-by: Shivaprasad G Bhat Closes: https://lore.kernel.org/all/e301014d-568f-4ed5-bc64-b8a85ca0b1e1@linux.ibm.com/ Fixes: 3424d8c18a7d ("Merge tag 'core-entry-2026-08-17' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip") Signed-off-by: Shrikanth Hegde Tested-by: Venkat Rao Bagalkote Tested-by: Shivaprasad G Bhat Reviewed-by: Mukesh Kumar Chaurasiya (IBM) Signed-off-by: Madhavan Srinivasan Link: https://patch.msgid.link/20260828053811.1042300-1-sshegde@linux.ibm.com --- arch/powerpc/kernel/syscall.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/arch/powerpc/kernel/syscall.c b/arch/powerpc/kernel/syscall.c index 4916c205c4bb..fbefe1927b10 100644 --- a/arch/powerpc/kernel/syscall.c +++ b/arch/powerpc/kernel/syscall.c @@ -18,8 +18,10 @@ notrace long system_call_exception(struct pt_regs *regs, unsigned long r0) long ret; syscall_fn f; - if (unlikely(!syscall_enter_from_user_mode_randomize_stack(regs, &r0))) + if (unlikely(!syscall_enter_from_user_mode_randomize_stack(regs, &r0))) { + clear_thread_flag(TIF_SYSCALL_RET); return syscall_get_error(current, regs); + } if (unlikely(test_and_clear_thread_flag(TIF_SYSCALL_RET))) return syscall_get_error(current, regs);