[PATCH AUTOSEL 5.4 175/205] um: Don't trace irqflags during shutdown

From: Sasha Levin
Date: Thu Jan 16 2020 - 14:19:37 EST


From: Johannes Berg <johannes.berg@xxxxxxxxx>

[ Upstream commit 5c1f33e2a03c0b8710b5d910a46f1e1fb0607679 ]

In the main() code, we eventually enable signals just before
exec() or exit(), in order to to not have signals pending and
delivered *after* the exec().

I've observed SIGSEGV loops at this point, and the reason seems
to be the irqflags tracing; this makes sense as the kernel is
no longer really functional at this point. Since there's really
no reason to use unblock_signals_trace() here (I had just done
a global search & replace), use the plain unblock_signals() in
this case to avoid going into the no longer functional kernel.

Fixes: 0dafcbe128d2 ("um: Implement TRACE_IRQFLAGS_SUPPORT")
Signed-off-by: Johannes Berg <johannes.berg@xxxxxxxxx>
Signed-off-by: Richard Weinberger <richard@xxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
arch/um/os-Linux/main.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/um/os-Linux/main.c b/arch/um/os-Linux/main.c
index 8014dfac644d..c8a42ecbd7a2 100644
--- a/arch/um/os-Linux/main.c
+++ b/arch/um/os-Linux/main.c
@@ -170,7 +170,7 @@ int __init main(int argc, char **argv, char **envp)
* that they won't be delivered after the exec, when
* they are definitely not expected.
*/
- unblock_signals_trace();
+ unblock_signals();

os_info("\n");
/* Reboot */
--
2.20.1