From 8de2109f4670c6560ea089886d97e06b15772256 Mon Sep 17 00:00:00 2001 From: Baoquan He Date: Fri, 22 Jan 2021 15:42:14 +0800 Subject: [PATCH] kernel: kexec: remove the lock operation of system_transition_mutex commit 56c91a18432b631ca18438841fd1831ef756cabf upstream. 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: 55f2503c3b69 ("PM / reboot: Eliminate race between reboot and suspend") Signed-off-by: Baoquan He Reported-by: Dan Carpenter Reviewed-by: Pingfan Liu Cc: 4.19+ # 4.19+ Signed-off-by: Rafael J. Wysocki Signed-off-by: Greg Kroah-Hartman --- kernel/kexec_core.c | 2 -- 1 file changed, 2 deletions(-) diff --git a/kernel/kexec_core.c b/kernel/kexec_core.c index 15d70a90b50d..d65b0fc8fb48 100644 --- a/kernel/kexec_core.c +++ b/kernel/kexec_core.c @@ -1129,7 +1129,6 @@ int kernel_kexec(void) #ifdef CONFIG_KEXEC_JUMP if (kexec_image->preserve_context) { - lock_system_sleep(); pm_prepare_console(); error = freeze_processes(); if (error) { @@ -1192,7 +1191,6 @@ int kernel_kexec(void) thaw_processes(); Restore_console: pm_restore_console(); - unlock_system_sleep(); } #endif