According to create_thread(3): "The new thread does not inherit the creating
thread's alternate signal stack". Since commit f9a3879a (Fix sigaltstack
corruption among cloned threads), current->sas_ss_size is set to 0 for cloned
processes sharing VM with their parent. Don't use the (nonexistent) alternate
signal stack in this case. This has been broken since commit 29c4dfd9 ([XTENSA]
Remove non-rt signal handling).
Fixes the SA_ONSTACK part of the nptl/tst-cancel20 test from uClibc.
Cc: <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Baruch Siach <baruch@xxxxxxxxxx>
---
v2: Use sas_ss_flags() as suggested by Max Filippov. Reword commit message.
arch/xtensa/kernel/signal.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/xtensa/kernel/signal.c b/arch/xtensa/kernel/signal.c
index 718eca1..98b67d5 100644
--- a/arch/xtensa/kernel/signal.c
+++ b/arch/xtensa/kernel/signal.c
@@ -341,7 +341,7 @@ static int setup_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
sp = regs->areg[1];
- if ((ka->sa.sa_flags & SA_ONSTACK) != 0 && ! on_sig_stack(sp)) {
+ if ((ka->sa.sa_flags & SA_ONSTACK) != 0 && sas_ss_flags(sp) == 0) {
sp = current->sas_ss_sp + current->sas_ss_size;
}
--
1.8.4.rc3
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