commit ab251dacfb upstream.
The field "eip" (instruction pointer) and "esp" (stack pointer) of a task
can be read from /proc/PID/stat. These fields can be interesting for
coredump.
However, these fields were disabled by commit 0a1eb2d474 ("fs/proc: Stop
reporting eip and esp in /proc/PID/stat"), because it is generally unsafe
to do so. But it is safe for a coredumping process, and therefore
exceptions were made:
- for a coredumping thread by commit fd7d56270b ("fs/proc: Report
eip/esp in /prod/PID/stat for coredumping").
- for all other threads in a coredumping process by commit cb8f381f16
("fs/proc/array.c: allow reporting eip/esp for all coredumping
threads").
The above two commits check the PF_DUMPCORE flag to determine a coredump thread
and the PF_EXITING flag for the other threads.
Unfortunately, commit 9230738308 ("coredump: Don't perform any cleanups
before dumping core") moved coredump to happen earlier and before PF_EXITING is
set. Thus, checking PF_EXITING is no longer the correct way to determine
threads in a coredumping process.
Instead of PF_EXITING, use PF_POSTCOREDUMP to determine the other threads.
Checking of PF_EXITING was added for coredumping, so it probably can now be
removed. But it doesn't hurt to keep.
Fixes: 9230738308 ("coredump: Don't perform any cleanups before dumping core")
Cc: stable@vger.kernel.org
Cc: Eric W. Biederman <ebiederm@xmission.com>
Acked-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Kees Cook <kees@kernel.org>
Signed-off-by: Nam Cao <namcao@linutronix.de>
Link: https://lore.kernel.org/r/d89af63d478d6c64cc46a01420b46fd6eb147d6f.1735805772.git.namcao@linutronix.de
Signed-off-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
553fbae0ef