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authorChanho Min <chanho.min@lge.com>2018-11-12 06:54:45 +0300
committerRafael J. Wysocki <rafael.j.wysocki@intel.com>2018-11-19 13:28:10 +0300
commitc22397888f1eed98cd59f0a88f2a5f6925f80e15 (patch)
tree259d23669c8d9da8237d881d41215826153440ef
parent9ff01193a20d391e8dbce4403dd5ef87c7eaaca6 (diff)
downloadlinux-c22397888f1eed98cd59f0a88f2a5f6925f80e15.tar.xz
exec: make de_thread() freezable
Suspend fails due to the exec family of functions blocking the freezer. The casue is that de_thread() sleeps in TASK_UNINTERRUPTIBLE waiting for all sub-threads to die, and we have the deadlock if one of them is frozen. This also can occur with the schedule() waiting for the group thread leader to exit if it is frozen. In our machine, it causes freeze timeout as bellows. Freezing of tasks failed after 20.010 seconds (1 tasks refusing to freeze, wq_busy=0): setcpushares-ls D ffffffc00008ed70 0 5817 1483 0x0040000d Call trace: [<ffffffc00008ed70>] __switch_to+0x88/0xa0 [<ffffffc000d1c30c>] __schedule+0x1bc/0x720 [<ffffffc000d1ca90>] schedule+0x40/0xa8 [<ffffffc0001cd784>] flush_old_exec+0xdc/0x640 [<ffffffc000220360>] load_elf_binary+0x2a8/0x1090 [<ffffffc0001ccff4>] search_binary_handler+0x9c/0x240 [<ffffffc00021c584>] load_script+0x20c/0x228 [<ffffffc0001ccff4>] search_binary_handler+0x9c/0x240 [<ffffffc0001ce8e0>] do_execveat_common.isra.14+0x4f8/0x6e8 [<ffffffc0001cedd0>] compat_SyS_execve+0x38/0x48 [<ffffffc00008de30>] el0_svc_naked+0x24/0x28 To fix this, make de_thread() freezable. It looks safe and works fine. Suggested-by: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Chanho Min <chanho.min@lge.com> Acked-by: Oleg Nesterov <oleg@redhat.com> Acked-by: Pavel Machek <pavel@ucw.cz> Acked-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
-rw-r--r--fs/exec.c5
1 files changed, 3 insertions, 2 deletions
diff --git a/fs/exec.c b/fs/exec.c
index fc281b738a98..acc3a5536384 100644
--- a/fs/exec.c
+++ b/fs/exec.c
@@ -62,6 +62,7 @@
#include <linux/oom.h>
#include <linux/compat.h>
#include <linux/vmalloc.h>
+#include <linux/freezer.h>
#include <linux/uaccess.h>
#include <asm/mmu_context.h>
@@ -1083,7 +1084,7 @@ static int de_thread(struct task_struct *tsk)
while (sig->notify_count) {
__set_current_state(TASK_KILLABLE);
spin_unlock_irq(lock);
- schedule();
+ freezable_schedule();
if (unlikely(__fatal_signal_pending(tsk)))
goto killed;
spin_lock_irq(lock);
@@ -1111,7 +1112,7 @@ static int de_thread(struct task_struct *tsk)
__set_current_state(TASK_KILLABLE);
write_unlock_irq(&tasklist_lock);
cgroup_threadgroup_change_end(tsk);
- schedule();
+ freezable_schedule();
if (unlikely(__fatal_signal_pending(tsk)))
goto killed;
}