possible deadlock in brd

possible deadlock in brd_probe
Status: upstream: reported C repro on 2020/11/17 10:30
Reported-by: syzbot+fd01c5d29a476390728d@syzkaller.appspotmail.com
First crash: 114d, last: 40m

Cause bisection: introduced by (bisect log) [merge commit]:
commit ee51814888278677cb4384814bbe3c95f6270b50
Author: Linus Torvalds <torvalds@linux-foundation.org>
Date: Fri Nov 6 20:21:33 2020 +0000

Merge tag 's390-5.10-3' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux

Crash: BUG: sleeping function called from invalid context in sta_info_move_state (log)
Repro: C syz .config

Sample crash report:

======================================================
WARNING: possible circular locking dependency detected
5.10.0-rc3-next-20201116-syzkaller #0 Not tainted
------------------------------------------------------
syz-executor541/8491 is trying to acquire lock:
ffffffff8bd213a8 (brd_devices_mutex){+.+.}-{3:3}, at: brd_probe+0x31/0x250 drivers/block/brd.c:434

but task is already holding lock:
ffffffff8bac3508 (major_names_lock){+.+.}-{3:3}, at: request_gendisk_module block/genhd.c:976 [inline]
ffffffff8bac3508 (major_names_lock){+.+.}-{3:3}, at: get_gendisk+0x3c8/0x6a0 block/genhd.c:1029

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #3 (major_names_lock){+.+.}-{3:3}:
       __mutex_lock_common kernel/locking/mutex.c:956 [inline]
       __mutex_lock+0x134/0x1110 kernel/locking/mutex.c:1103
       __register_blkdev+0x2b/0x390 block/genhd.c:449
       register_mtd_blktrans+0x85/0x3c0 drivers/mtd/mtd_blkdevs.c:534
       do_one_initcall+0x103/0x650 init/main.c:1222
       do_initcall_level init/main.c:1295 [inline]
       do_initcalls init/main.c:1311 [inline]
       do_basic_setup init/main.c:1331 [inline]
       kernel_init_freeable+0x600/0x684 init/main.c:1531
       kernel_init+0xd/0x1b8 init/main.c:1420
       ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:296

-> #2 (mtd_table_mutex){+.+.}-{3:3}:
       __mutex_lock_common kernel/locking/mutex.c:956 [inline]
       __mutex_lock+0x134/0x1110 kernel/locking/mutex.c:1103
       blktrans_open+0x69/0x600 drivers/mtd/mtd_blkdevs.c:212
       __blkdev_get+0x80f/0x1870 fs/block_dev.c:1494
       blkdev_get+0xd1/0x240 fs/block_dev.c:1634
       blkdev_open+0x21d/0x2b0 fs/block_dev.c:1751
       do_dentry_open+0x4b9/0x11b0 fs/open.c:817
       do_open fs/namei.c:3252 [inline]
       path_openat+0x1b9a/0x2730 fs/namei.c:3369
       do_filp_open+0x17e/0x3c0 fs/namei.c:3396
       do_sys_openat2+0x16d/0x420 fs/open.c:1168
       do_sys_open fs/open.c:1184 [inline]
       __do_sys_open fs/open.c:1192 [inline]
       __se_sys_open fs/open.c:1188 [inline]
       __x64_sys_open+0x119/0x1c0 fs/open.c:1188
       do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
       entry_SYSCALL_64_after_hwframe+0x44/0xa9

-> #1 (&bdev->bd_mutex){+.+.}-{3:3}:
       __mutex_lock_common kernel/locking/mutex.c:956 [inline]
       __mutex_lock+0x134/0x1110 kernel/locking/mutex.c:1103
       __blkdev_get+0x457/0x1870 fs/block_dev.c:1479
       blkdev_get+0xd1/0x240 fs/block_dev.c:1634
       blkdev_get_by_dev+0x3b/0x70 fs/block_dev.c:1715
       disk_scan_partitions block/genhd.c:677 [inline]
       register_disk block/genhd.c:727 [inline]
       __device_add_disk+0xe02/0x1250 block/genhd.c:814
       add_disk include/linux/genhd.h:295 [inline]
       brd_init+0x2af/0x475 drivers/block/brd.c:518
       do_one_initcall+0x103/0x650 init/main.c:1222
       do_initcall_level init/main.c:1295 [inline]
       do_initcalls init/main.c:1311 [inline]
       do_basic_setup init/main.c:1331 [inline]
       kernel_init_freeable+0x600/0x684 init/main.c:1531
       kernel_init+0xd/0x1b8 init/main.c:1420
       ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:296

-> #0 (brd_devices_mutex){+.+.}-{3:3}:
       check_prev_add kernel/locking/lockdep.c:2866 [inline]
       check_prevs_add kernel/locking/lockdep.c:2991 [inline]
       validate_chain kernel/locking/lockdep.c:3606 [inline]
       __lock_acquire+0x2ca6/0x5c00 kernel/locking/lockdep.c:4830
       lock_acquire kernel/locking/lockdep.c:5435 [inline]
       lock_acquire+0x2a3/0x8c0 kernel/locking/lockdep.c:5400
       __mutex_lock_common kernel/locking/mutex.c:956 [inline]
       __mutex_lock+0x134/0x1110 kernel/locking/mutex.c:1103
       brd_probe+0x31/0x250 drivers/block/brd.c:434
       request_gendisk_module block/genhd.c:979 [inline]
       get_gendisk+0x4c3/0x6a0 block/genhd.c:1029
       bdev_get_gendisk fs/block_dev.c:1094 [inline]
       __blkdev_get+0x344/0x1870 fs/block_dev.c:1455
       blkdev_get+0xd1/0x240 fs/block_dev.c:1634
       blkdev_open+0x21d/0x2b0 fs/block_dev.c:1751
       do_dentry_open+0x4b9/0x11b0 fs/open.c:817
       do_open fs/namei.c:3252 [inline]
       path_openat+0x1b9a/0x2730 fs/namei.c:3369
       do_filp_open+0x17e/0x3c0 fs/namei.c:3396
       do_sys_openat2+0x16d/0x420 fs/open.c:1168
       do_sys_open fs/open.c:1184 [inline]
       __do_sys_openat fs/open.c:1200 [inline]
       __se_sys_openat fs/open.c:1195 [inline]
       __x64_sys_openat+0x13f/0x1f0 fs/open.c:1195
       do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
       entry_SYSCALL_64_after_hwframe+0x44/0xa9

other info that might help us debug this:

Chain exists of:
  brd_devices_mutex --> mtd_table_mutex --> major_names_lock

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(major_names_lock);
                               lock(mtd_table_mutex);
                               lock(major_names_lock);
  lock(brd_devices_mutex);

 *** DEADLOCK ***

1 lock held by syz-executor541/8491:
 #0: ffffffff8bac3508 (major_names_lock){+.+.}-{3:3}, at: request_gendisk_module block/genhd.c:976 [inline]
 #0: ffffffff8bac3508 (major_names_lock){+.+.}-{3:3}, at: get_gendisk+0x3c8/0x6a0 block/genhd.c:1029

stack backtrace:
CPU: 0 PID: 8491 Comm: syz-executor541 Not tainted 5.10.0-rc3-next-20201116-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:79 [inline]
 dump_stack+0x107/0x163 lib/dump_stack.c:120
 check_noncircular+0x25f/0x2e0 kernel/locking/lockdep.c:2115
 check_prev_add kernel/locking/lockdep.c:2866 [inline]
 check_prevs_add kernel/locking/lockdep.c:2991 [inline]
 validate_chain kernel/locking/lockdep.c:3606 [inline]
 __lock_acquire+0x2ca6/0x5c00 kernel/locking/lockdep.c:4830
 lock_acquire kernel/locking/lockdep.c:5435 [inline]
 lock_acquire+0x2a3/0x8c0 kernel/locking/lockdep.c:5400
 __mutex_lock_common kernel/locking/mutex.c:956 [inline]
 __mutex_lock+0x134/0x1110 kernel/locking/mutex.c:1103
 brd_probe+0x31/0x250 drivers/block/brd.c:434
 request_gendisk_module block/genhd.c:979 [inline]
 get_gendisk+0x4c3/0x6a0 block/genhd.c:1029
 bdev_get_gendisk fs/block_dev.c:1094 [inline]
 __blkdev_get+0x344/0x1870 fs/block_dev.c:1455
 blkdev_get+0xd1/0x240 fs/block_dev.c:1634
 blkdev_open+0x21d/0x2b0 fs/block_dev.c:1751
 do_dentry_open+0x4b9/0x11b0 fs/open.c:817
 do_open fs/namei.c:3252 [inline]
 path_openat+0x1b9a/0x2730 fs/namei.c:3369
 do_filp_open+0x17e/0x3c0 fs/namei.c:3396
 do_sys_openat2+0x16d/0x420 fs/open.c:1168
 do_sys_open fs/open.c:1184 [inline]
 __do_sys_openat fs/open.c:1200 [inline]
 __se_sys_openat fs/open.c:1195 [inline]
 __x64_sys_openat+0x13f/0x1f0 fs/open.c:1195
 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x445ec9
Code: e8 fc b8 02 00 48 83 c4 18 c3 0f 1f 80 00 00 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 0b 12 fc ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007f6bca748d98 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00000000006ddc38 RCX: 0000000000445ec9
RDX: 0000000000000000 RSI: 0000000020002040 RDI: 00000000ffffff9c

Crashes (6084):
Manager	Time	Kernel	Commit	Syzkaller	Config	Log	Report	Syz repro	C repro	VM info	Title
ci-upstream-linux-next-kasan-gce-root	2020/11/16 15:57	linux-next	03430750	1bf9a662	.config	log	report	syz	C
ci-upstream-kasan-gce-smack-root	2021/03/07 20:51	upstream	a38fd874	75506d9c	.config	log	report			info	possible deadlock in brd_probe
ci-upstream-kasan-gce-root	2021/03/07 18:53	upstream	a38fd874	75506d9c	.config	log	report			info	possible deadlock in brd_probe
ci-upstream-kasan-gce-root	2021/03/07 17:22	upstream	a38fd874	75506d9c	.config	log	report			info	possible deadlock in brd_probe
ci-upstream-kasan-gce-root	2021/03/07 12:34	upstream	a38fd874	75506d9c	.config	log	report			info	possible deadlock in brd_probe
ci-qemu-upstream	2021/03/07 09:44	upstream	280d542f	c599ed12	.config	log	report			info	possible deadlock in brd_probe
ci-upstream-kasan-gce-selinux-root	2021/03/07 07:25	upstream	a38fd874	e4b4d570	.config	log	report			info	possible deadlock in brd_probe
ci-upstream-kasan-gce-selinux-root	2021/03/07 06:20	upstream	a38fd874	e4b4d570	.config	log	report			info	possible deadlock in brd_probe
ci-upstream-kasan-gce-selinux-root	2021/03/07 05:16	upstream	a38fd874	e4b4d570	.config	log	report			info	possible deadlock in brd_probe
ci-upstream-kasan-gce-selinux-root	2021/03/07 01:52	upstream	a38fd874	e4b4d570	.config	log	report			info	possible deadlock in brd_probe
ci-upstream-kasan-gce-root	2021/03/07 00:53	upstream	a38fd874	e4b4d570	.config	log	report			info	possible deadlock in brd_probe
ci-upstream-kasan-gce-selinux-root	2021/03/06 23:08	upstream	a38fd874	e4b4d570	.config	log	report			info	possible deadlock in brd_probe
ci-upstream-kasan-gce-root	2021/03/06 20:55	upstream	a38fd874	e4b4d570	.config	log	report			info	possible deadlock in brd_probe
ci-upstream-kasan-gce-root	2021/03/06 17:34	upstream	a38fd874	e4b4d570	.config	log	report			info	possible deadlock in brd_probe
ci-upstream-kasan-gce-root	2021/03/06 16:22	upstream	a38fd874	e4b4d570	.config	log	report			info	possible deadlock in brd_probe
ci-upstream-kasan-gce-root	2021/03/06 13:52	upstream	a38fd874	e4b4d570	.config	log	report			info	possible deadlock in brd_probe
ci-upstream-kasan-gce-root	2021/03/06 11:59	upstream	a38fd874	e4b4d570	.config	log	report			info	possible deadlock in brd_probe
ci-upstream-kasan-gce-root	2021/03/06 10:02	upstream	280d542f	56722561	.config	log	report			info	possible deadlock in brd_probe
ci-upstream-kasan-gce-root	2021/03/06 07:06	upstream	280d542f	56722561	.config	log	report			info	possible deadlock in brd_probe
ci-upstream-kasan-gce-root	2021/03/06 04:07	upstream	280d542f	56722561	.config	log	report			info	possible deadlock in brd_probe
ci-upstream-kasan-gce-root	2021/03/06 03:04	upstream	280d542f	56722561	.config	log	report			info	possible deadlock in brd_probe
ci-upstream-kasan-gce-root	2021/03/06 02:27	upstream	280d542f	56722561	.config	log	report			info	possible deadlock in brd_probe
ci-qemu-upstream	2021/03/06 01:14	upstream	280d542f	e4b4d570	.config	log	report			info	possible deadlock in brd_probe
ci-upstream-kasan-gce-smack-root	2021/03/05 19:15	upstream	280d542f	9d751681	.config	log	report			info	possible deadlock in brd_probe
ci-upstream-kasan-gce-root	2021/03/05 16:40	upstream	280d542f	9d751681	.config	log	report			info	possible deadlock in brd_probe
ci-upstream-kasan-gce-root	2021/03/05 14:55	upstream	280d542f	9d751681	.config	log	report			info	possible deadlock in brd_probe
ci-upstream-kasan-gce-selinux-root	2021/03/05 13:52	upstream	280d542f	9d751681	.config	log	report			info	possible deadlock in brd_probe
ci-upstream-kasan-gce-selinux-root	2021/03/05 12:18	upstream	280d542f	9d751681	.config	log	report			info	possible deadlock in brd_probe
ci-qemu-upstream	2021/03/05 09:49	upstream	280d542f	9d751681	.config	log	report			info	possible deadlock in brd_probe
ci-upstream-kasan-gce-root	2021/03/05 08:49	upstream	cee407c5	9d751681	.config	log	report			info	possible deadlock in brd_probe
ci-upstream-kasan-gce-root	2021/03/05 04:40	upstream	cee407c5	9d751681	.config	log	report			info	possible deadlock in brd_probe
ci-upstream-kasan-gce-selinux-root	2021/03/05 02:33	upstream	cee407c5	9d751681	.config	log	report			info	possible deadlock in brd_probe
ci-upstream-kasan-gce-selinux-root	2021/03/05 01:35	upstream	cee407c5	9d751681	.config	log	report			info	possible deadlock in brd_probe
ci-upstream-kasan-gce-root	2021/03/05 00:12	upstream	cee407c5	9d751681	.config	log	report			info	possible deadlock in brd_probe
ci-upstream-kasan-gce-selinux-root	2021/03/04 22:29	upstream	cee407c5	9d751681	.config	log	report			info	possible deadlock in brd_probe
ci-upstream-kasan-gce-selinux-root	2021/03/04 22:27	upstream	cee407c5	9d751681	.config	log	report			info	possible deadlock in brd_probe
ci-upstream-kasan-gce-smack-root	2021/03/04 21:13	upstream	cee407c5	9d751681	.config	log	report			info	possible deadlock in brd_probe
ci-upstream-kasan-gce-selinux-root	2021/03/04 16:13	upstream	f69d02e3	d7e4e604	.config	log	report			info	possible deadlock in brd_probe
ci-upstream-kasan-gce-selinux-root	2021/03/04 13:27	upstream	f69d02e3	d7e4e604	.config	log	report			info	possible deadlock in brd_probe
ci-qemu-upstream-386	2021/03/07 11:27	upstream	280d542f	c599ed12	.config	log	report			info	possible deadlock in brd_probe
ci-qemu-upstream-386	2021/03/07 08:39	upstream	280d542f	c599ed12	.config	log	report			info	possible deadlock in brd_probe
ci-qemu-upstream-386	2021/03/06 00:06	upstream	280d542f	e4b4d570	.config	log	report			info	possible deadlock in brd_probe
ci-qemu-upstream-386	2021/03/05 21:16	upstream	280d542f	e4b4d570	.config	log	report			info	possible deadlock in brd_probe
ci-qemu-upstream-386	2021/03/05 15:32	upstream	280d542f	9d751681	.config	log	report			info	possible deadlock in brd_probe
ci-qemu-upstream-386	2021/03/04 18:57	upstream	f69d02e3	f89ed068	.config	log	report			info	possible deadlock in brd_probe
ci-upstream-linux-next-kasan-gce-root	2021/03/07 18:49	linux-next	4641b323	75506d9c	.config	log	report			info	possible deadlock in brd_probe
ci-upstream-linux-next-kasan-gce-root	2021/03/06 18:59	linux-next	4641b323	e4b4d570	.config	log	report			info	possible deadlock in brd_probe
ci-upstream-linux-next-kasan-gce-root	2021/03/05 11:23	linux-next	4641b323	9d751681	.config	log	report			info	possible deadlock in brd_probe
ci-upstream-linux-next-kasan-gce-root	2021/03/04 20:05	linux-next	f5427c24	9d751681	.config	log	report			info	possible deadlock in brd_probe
ci-upstream-linux-next-kasan-gce-root	2021/01/17 14:27	linux-next	b3a3cbde	813be542	.config	log	report			info
ci-upstream-linux-next-kasan-gce-root	2020/11/13 10:21	linux-next	92edc4ae	16fca0c8	.config	log	report			info