signal: avoid unconditional siginfo copy in send_signal_locked()

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send_signal_locked() unconditionally copies siginfo before the namespace
translation to avoid corrupting a shared siginfo.

Not that I think this can actually hurt performance-wise, just it doesn't
look clean to me; the copy is only needed in the unlikely case when the
translation will actually change something.

Defer it to the two cases where si_pid/si_uid are rewritten, and while at
it add #ifdef's just for completeness.

Link: https://lore.kernel.org/akkaAgNfUby5_3nM@redhat.com
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Reviewed-by: Bradley Morgan <include@grrlz.net>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Eric Biederman <ebiederm@xmission.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

...

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Oleg Nesterov 2026-07-04 16:34:42 +02:00 • committed by Andrew Morton

parent 306d71b091

commit 571999ccd1

1 changed files with 15 additions and 8 deletions

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kernel/signal.c

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