From: Tiwei Bie <[email protected]> commit f68b2d5a907b53eed99cf2efcaaae116df73c298 upstream
We rely on errno to determine whether a syscall has failed, so we need to ensure that accessing errno is async-signal-safe. Currently, we preserve the errno in sig_handler_common(), but it doesn't cover every possible case. Let's do it in hard_handler() instead, which is the signal handler we actually register. Signed-off-by: Tiwei Bie <[email protected]> Link: https://patch.msgid.link/[email protected] Signed-off-by: Johannes Berg <[email protected]> [florian: hard_handler() in 6.12 retains the to_irq_stack/from_irq_stack loop from before the upstream SMP refactoring; errno save/restore is wrapped around that loop rather than replacing sig_handler_common's existing save/restore] Signed-off-by: Florian Fainelli <[email protected]> --- arch/um/os-Linux/signal.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/arch/um/os-Linux/signal.c b/arch/um/os-Linux/signal.c index b11ed66c8bb0..94abc9e3ec7e 100644 --- a/arch/um/os-Linux/signal.c +++ b/arch/um/os-Linux/signal.c @@ -190,6 +190,7 @@ static void hard_handler(int sig, siginfo_t *si, void *p) { ucontext_t *uc = p; mcontext_t *mc = &uc->uc_mcontext; + int save_errno = errno; unsigned long pending = 1UL << sig; do { @@ -227,6 +228,8 @@ static void hard_handler(int sig, siginfo_t *si, void *p) if (!nested) pending = from_irq_stack(nested); } while (pending); + + errno = save_errno; } void set_handler(int sig) -- 2.34.1
