The default behavior of multipathd is to run kpartx against newly
discovered paths. Avoid that these kpartx processes become unkillable
if there are no paths left and when using queue_if_no_path. This patch
avoids that kpartx sporadically hangs as follows:
Call Trace:
__schedule+0x3df/0xc10
schedule+0x3d/0x90
io_schedule+0x16/0x40
__lock_page+0x111/0x140
truncate_inode_pages_range+0x462/0x790
truncate_inode_pages+0x15/0x20
kill_bdev+0x35/0x40
__blkdev_put+0x76/0x220
blkdev_put+0x4e/0x170
blkdev_close+0x25/0x30
__fput+0xed/0x1f0
____fput+0xe/0x10
task_work_run+0x85/0xc0
do_exit+0x311/0xc70
do_group_exit+0x50/0xd0
get_signal+0x2c7/0x930
do_signal+0x28/0x6b0
exit_to_usermode_loop+0x62/0xa0
do_syscall_64+0xda/0x140
entry_SYSCALL64_slow_path+0x25/0x25
Signed-off-by: Bart Van Assche <bart.vanassche@xxxxxxxxxxx>
Cc: Oleg Nesterov <oleg@xxxxxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxxx>
Cc: Mel Gorman <mgorman@xxxxxxxxxxxxxxxxxxx>
Cc: Hugh Dickins <hughd@xxxxxxxxxx>
Cc: Mike Snitzer <snitzer@xxxxxxxxxx>
Cc: Jan Kara <jack@xxxxxxx>
Cc: Hannes Reinecke <hare@xxxxxxxx>
Cc: linux-mm@xxxxxxxxx
---
mm/truncate.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/mm/truncate.c b/mm/truncate.c
index 6263affdef88..91abd16d74f8 100644
--- a/mm/truncate.c
+++ b/mm/truncate.c
@@ -20,6 +20,7 @@
#include <linux/task_io_accounting_ops.h>
#include <linux/buffer_head.h> /* grr. try_to_release_page,
do_invalidatepage */
+#include <linux/sched/signal.h>
#include <linux/shmem_fs.h>
#include <linux/cleancache.h>
#include <linux/rmap.h>
@@ -366,7 +367,7 @@ void truncate_inode_pages_range(struct address_space *mapping,
return;
index = start;
- for ( ; ; ) {
+ for ( ; !signal_pending_state(TASK_WAKEKILL, current); ) {
cond_resched();
if (!pagevec_lookup_entries(&pvec, mapping, index,
min(end - index, (pgoff_t)PAGEVEC_SIZE), indices)) {
@@ -400,7 +401,8 @@ void truncate_inode_pages_range(struct address_space *mapping,
continue;
}
- lock_page(page);
+ if (lock_page_killable(page))
+ break;
WARN_ON(page_to_index(page) != index);
wait_on_page_writeback(page);
truncate_inode_page(mapping, page);
--
2.12.2
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