* Re: + signal-move-print_dropped_signal.patch added to -mm tree
[not found] <20200102215029.PWaCMXI_O%akpm@linux-foundation.org>
@ 2020-01-03 10:06 ` Oleg Nesterov
0 siblings, 0 replies; only message in thread
From: Oleg Nesterov @ 2020-01-03 10:06 UTC (permalink / raw)
To: akpm
Cc: arnd, christian.brauner, deepa.kernel, ebiederm, guro,
linux-kernel, trix
> From: Tom Rix <trix@redhat.com>
> Subject: kernel/signal.c: move print_dropped_signal
>
> If the allocation of 'q' fails, the signal will be dropped.
Well, not necessarily... See the comment above TRACE_SIGNAL_LOSE_INFO
in __send_signal().
> To ensure
> that this is reported, move print_dropped_signal to be inside the '(q ==
> NULL)' if-check.
OK, but print_dropped_signal() says "reached RLIMIT_SIGPENDING", this
is misleading if kmem_cache_alloc() fails.
> Link: http://lkml.kernel.org/r/20191203180221.7038-1-trix@redhat.com
> Signed-off-by: Tom Rix <trix@redhat.com>
> Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
> Cc: "Eric W. Biederman" <ebiederm@xmission.com>
> Cc: Christian Brauner <christian.brauner@ubuntu.com>
> Cc: Arnd Bergmann <arnd@arndb.de>
> Cc: Roman Gushchin <guro@fb.com>
> Cc: Deepa Dinamani <deepa.kernel@gmail.com>
> Cc: Oleg Nesterov <oleg@redhat.com>
> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
> ---
>
> kernel/signal.c | 3 +--
> 1 file changed, 1 insertion(+), 2 deletions(-)
>
> --- a/kernel/signal.c~signal-move-print_dropped_signal
> +++ a/kernel/signal.c
> @@ -427,11 +427,10 @@ __sigqueue_alloc(int sig, struct task_st
> atomic_read(&user->sigpending) <=
> task_rlimit(t, RLIMIT_SIGPENDING)) {
> q = kmem_cache_alloc(sigqueue_cachep, flags);
> - } else {
> - print_dropped_signal(sig);
> }
>
> if (unlikely(q == NULL)) {
> + print_dropped_signal(sig);
> atomic_dec(&user->sigpending);
> free_uid(user);
> } else {
> _
>
> Patches currently in -mm which might be from trix@redhat.com are
>
> signal-move-print_dropped_signal.patch
>
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