linux_dsm_epyc7002/drivers/block
Jack Wang 6f7a362e1c block/rnbd-clt: avoid module unload race with close confirmation
commit 3a21777c6ee99749bac10727b3c17e5bcfebe5c1 upstream.

We had kernel panic, it is caused by unload module and last
close confirmation.

call trace:
[1196029.743127]  free_sess+0x15/0x50 [rtrs_client]
[1196029.743128]  rtrs_clt_close+0x4c/0x70 [rtrs_client]
[1196029.743129]  ? rnbd_clt_unmap_device+0x1b0/0x1b0 [rnbd_client]
[1196029.743130]  close_rtrs+0x25/0x50 [rnbd_client]
[1196029.743131]  rnbd_client_exit+0x93/0xb99 [rnbd_client]
[1196029.743132]  __x64_sys_delete_module+0x190/0x260

And in the crashdump confirmation kworker is also running.
PID: 6943   TASK: ffff9e2ac8098000  CPU: 4   COMMAND: "kworker/4:2"
 #0 [ffffb206cf337c30] __schedule at ffffffff9f93f891
 #1 [ffffb206cf337cc8] schedule at ffffffff9f93fe98
 #2 [ffffb206cf337cd0] schedule_timeout at ffffffff9f943938
 #3 [ffffb206cf337d50] wait_for_completion at ffffffff9f9410a7
 #4 [ffffb206cf337da0] __flush_work at ffffffff9f08ce0e
 #5 [ffffb206cf337e20] rtrs_clt_close_conns at ffffffffc0d5f668 [rtrs_client]
 #6 [ffffb206cf337e48] rtrs_clt_close at ffffffffc0d5f801 [rtrs_client]
 #7 [ffffb206cf337e68] close_rtrs at ffffffffc0d26255 [rnbd_client]
 #8 [ffffb206cf337e78] free_sess at ffffffffc0d262ad [rnbd_client]
 #9 [ffffb206cf337e88] rnbd_clt_put_dev at ffffffffc0d266a7 [rnbd_client]

The problem is both code path try to close same session, which lead to
panic.

To fix it, just skip the sess if the refcount already drop to 0.

Fixes: f7a7a5c228 ("block/rnbd: client: main functionality")
Signed-off-by: Jack Wang <jinpu.wang@cloud.ionos.com>
Reviewed-by: Gioh Kim <gi-oh.kim@cloud.ionos.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-01-17 14:17:05 +01:00
..
aoe block: lift setting the readahead size into the block layer 2020-09-24 13:43:39 -06:00
drbd block-5.10-2020-10-12 2020-10-13 12:12:44 -07:00
mtip32xx blk-mq: move failure injection out of blk_mq_complete_request 2020-06-24 09:15:57 -06:00
paride paride/pcd: use bdev_check_media_change 2020-09-10 09:32:31 -06:00
rnbd block/rnbd-clt: avoid module unload race with close confirmation 2021-01-17 14:17:05 +01:00
rsxx rsxx: Use fallthrough pseudo-keyword 2020-10-02 17:54:45 -06:00
xen-blkback xen/xenbus: Add 'will_handle' callback support in xenbus_watch_path() 2020-12-30 11:54:26 +01:00
zram block-5.10-2020-10-24 2020-10-24 12:46:42 -07:00
amiflop.c amiflop: use bdev_check_media_change 2020-09-10 09:32:30 -06:00
ataflop.c ataflop: use bdev_check_media_change 2020-09-10 09:32:30 -06:00
brd.c bdi: remove BDI_CAP_SYNCHRONOUS_IO 2020-09-24 13:43:39 -06:00
cryptoloop.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 30 2019-05-24 17:27:10 +02:00
floppy.c floppy: use bdev_check_media_change 2020-09-10 09:32:30 -06:00
Kconfig block: rsxx: select CONFIG_CRC32 2021-01-17 14:17:03 +01:00
loop.c loop: Fix occasional uevent drop 2020-11-12 13:59:04 -07:00
loop.h block/loop: Use global lock for ioctl() operation. 2018-11-08 06:30:11 -07:00
Makefile block/rnbd: include client and server modules into kernel compilation 2020-05-17 18:57:17 -03:00
nbd.c nbd: fix a block_device refcount leak in nbd_release 2020-11-10 08:01:28 -07:00
null_blk_main.c null_blk: add support for max open/active zone limit for zoned devices 2020-09-29 08:12:48 -06:00
null_blk_trace.c null_blk: add tracepoint helpers for zoned mode 2020-03-27 13:39:10 -06:00
null_blk_trace.h null_blk: add tracepoint helpers for zoned mode 2020-03-27 13:39:10 -06:00
null_blk_zoned.c null_blk: Fail zone append to conventional zones 2020-12-30 11:54:29 +01:00
null_blk.h null_blk: Fix scheduling in atomic with zoned mode 2020-11-06 09:36:42 -07:00
pktcdvd.c pktcdvd: use blkdev_get_by_dev instead of open coding it 2020-09-23 10:43:19 -06:00
ps3disk.c ps3disk: use the default segment boundary 2020-05-19 00:10:35 +10:00
ps3vram.c block: move ->make_request_fn to struct block_device_operations 2020-07-01 07:27:24 -06:00
rbd_types.h libceph, rbd: replace zero-length array with flexible-array 2020-06-01 13:22:53 +02:00
rbd.c We have: 2020-10-21 10:34:10 -07:00
skd_main.c skd_main: remove unused including <linux/version.h> 2020-10-17 08:11:14 -06:00
skd_s1120.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 497 2019-06-19 17:09:53 +02:00
sunvdc.c compat_ioctl: block: handle cdrom compat ioctl in non-cdrom drivers 2020-01-03 09:33:15 +01:00
swim3.c swim3: use bdev_check_media_changed 2020-09-10 09:32:31 -06:00
swim_asm.S treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
swim.c swim: simplify media change handling 2020-09-10 09:32:30 -06:00
sx8.c sx8: use a per-host tag_set 2018-11-09 08:14:14 -07:00
umem.c block: move ->make_request_fn to struct block_device_operations 2020-07-01 07:27:24 -06:00
umem.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 348 2019-06-05 17:37:08 +02:00
virtio_blk.c block: add a new revalidate_disk_size helper 2020-09-02 08:00:07 -06:00
xen-blkfront.c xen-blkfront: add a parameter for disabling of persistent grants 2020-10-21 07:15:15 -05:00
xsysace.c xsysace: use platform_get_resource() and platform_get_irq_optional() 2020-10-29 08:22:33 -06:00
z2ram.c mm: reorder includes after introduction of linux/pgtable.h 2020-06-09 09:39:13 -07:00