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kernel: kexec: remove the lock operation of system_transition_mutex

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Function kernel_kexec() is called with lock system_transition_mutex
held in reboot system call. While inside kernel_kexec(), it will
acquire system_transition_mutex agin. This will lead to dead lock.

The dead lock should be easily triggered, it hasn't caused any
failure report just because the feature 'kexec jump' is almost not
used by anyone as far as I know. An inquiry can be made about who
is using 'kexec jump' and where it's used. Before that, let's simply
remove the lock operation inside CONFIG_KEXEC_JUMP ifdeffery scope.

Fixes: 55f2503c3b ("PM / reboot: Eliminate race between reboot and suspend")
Signed-off-by: Baoquan He <bhe@redhat.com>
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: Pingfan Liu <kernelfans@gmail.com>
Cc: 4.19+ <stable@vger.kernel.org> # 4.19+
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
This commit is contained in:
Baoquan He 2021-01-22 15:42:14 +08:00 committed by Rafael J. Wysocki
parent 6ee1d745b7
commit 56c91a1843
1 changed files with 0 additions and 2 deletions
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2
kernel/kexec_core.c
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@ -1134,7 +1134,6 @@ int kernel_kexec(void)
#ifdef CONFIG_KEXEC_JUMP
if (kexec_image->preserve_context) {
lock_system_sleep();
pm_prepare_console();
error = freeze_processes();
if (error) {
@ -1197,7 +1196,6 @@ int kernel_kexec(void)
thaw_processes();
Restore_console:
pm_restore_console();
unlock_system_sleep();
}
#endif