possible deadlock in blkdev_reread

[upstream] possible deadlock in blkdev_reread_part
Status: upstream: reported C repro on 2017/11/01 19:01
Reported-by: syzbot+4684a000d5abdade83fac55b1e7d1f935ef1936e@syzkaller.appspotmail.com
First: 365d, last: 23h24m

Sample crash report:

======================================================
WARNING: possible circular locking dependency detected
4.14.0-rc2+ #10 Not tainted
------------------------------------------------------
syzkaller821047/2981 is trying to acquire lock:
 (&bdev->bd_mutex){+.+.}, at: [<ffffffff8232c60e>] blkdev_reread_part+0x1e/0x40 block/ioctl.c:192

but task is already holding lock:
 (&lo->lo_ctl_mutex#2){+.+.}, at: [<ffffffff83541ef9>] lo_compat_ioctl+0x109/0x140 drivers/block/loop.c:1533

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #1 (&lo->lo_ctl_mutex#2){+.+.}:
       check_prevs_add kernel/locking/lockdep.c:2020 [inline]
       validate_chain kernel/locking/lockdep.c:2469 [inline]
       __lock_acquire+0x328f/0x4620 kernel/locking/lockdep.c:3498
       lock_acquire+0x1d5/0x580 kernel/locking/lockdep.c:4002
       __mutex_lock_common kernel/locking/mutex.c:756 [inline]
       __mutex_lock+0x16f/0x19d0 kernel/locking/mutex.c:893
       mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:908
       lo_release+0x6b/0x180 drivers/block/loop.c:1587
       __blkdev_put+0x602/0x7c0 fs/block_dev.c:1780
       blkdev_put+0x85/0x4f0 fs/block_dev.c:1845
       blkdev_close+0x91/0xc0 fs/block_dev.c:1852
       __fput+0x333/0x7f0 fs/file_table.c:210
       ____fput+0x15/0x20 fs/file_table.c:244
       task_work_run+0x199/0x270 kernel/task_work.c:112
       tracehook_notify_resume include/linux/tracehook.h:191 [inline]
       exit_to_usermode_loop+0x296/0x310 arch/x86/entry/common.c:162
       prepare_exit_to_usermode arch/x86/entry/common.c:197 [inline]
       syscall_return_slowpath+0x42f/0x510 arch/x86/entry/common.c:266
       entry_SYSCALL_64_fastpath+0xbc/0xbe

-> #0 (&bdev->bd_mutex){+.+.}:
       check_prev_add+0x865/0x1520 kernel/locking/lockdep.c:1894
       check_prevs_add kernel/locking/lockdep.c:2020 [inline]
       validate_chain kernel/locking/lockdep.c:2469 [inline]
       __lock_acquire+0x328f/0x4620 kernel/locking/lockdep.c:3498
       lock_acquire+0x1d5/0x580 kernel/locking/lockdep.c:4002
       __mutex_lock_common kernel/locking/mutex.c:756 [inline]
       __mutex_lock+0x16f/0x19d0 kernel/locking/mutex.c:893
       mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:908
       blkdev_reread_part+0x1e/0x40 block/ioctl.c:192
       loop_reread_partitions+0x12f/0x1a0 drivers/block/loop.c:614
       loop_set_status+0x9ba/0xf60 drivers/block/loop.c:1156
       loop_set_status_compat+0x92/0xf0 drivers/block/loop.c:1506
       lo_compat_ioctl+0x114/0x140 drivers/block/loop.c:1534
       compat_blkdev_ioctl+0x3ba/0x1850 block/compat_ioctl.c:405
       C_SYSC_ioctl fs/compat_ioctl.c:1593 [inline]
       compat_SyS_ioctl+0x1d7/0x3290 fs/compat_ioctl.c:1540
       do_syscall_32_irqs_on arch/x86/entry/common.c:329 [inline]
       do_fast_syscall_32+0x3f2/0xf05 arch/x86/entry/common.c:391
       entry_SYSENTER_compat+0x51/0x60 arch/x86/entry/entry_64_compat.S:124

other info that might help us debug this:

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(&lo->lo_ctl_mutex#2);
                               lock(&bdev->bd_mutex);
                               lock(&lo->lo_ctl_mutex#2);
  lock(&bdev->bd_mutex);

 *** DEADLOCK ***

1 lock held by syzkaller821047/2981:
 #0:  (&lo->lo_ctl_mutex#2){+.+.}, at: [<ffffffff83541ef9>] lo_compat_ioctl+0x109/0x140 drivers/block/loop.c:1533

stack backtrace:
CPU: 0 PID: 2981 Comm: syzkaller821047 Not tainted 4.14.0-rc2+ #10
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:16 [inline]
 dump_stack+0x194/0x257 lib/dump_stack.c:52
 print_circular_bug+0x503/0x710 kernel/locking/lockdep.c:1259
 check_prev_add+0x865/0x1520 kernel/locking/lockdep.c:1894
 check_prevs_add kernel/locking/lockdep.c:2020 [inline]
 validate_chain kernel/locking/lockdep.c:2469 [inline]
 __lock_acquire+0x328f/0x4620 kernel/locking/lockdep.c:3498
 lock_acquire+0x1d5/0x580 kernel/locking/lockdep.c:4002
 __mutex_lock_common kernel/locking/mutex.c:756 [inline]
 __mutex_lock+0x16f/0x19d0 kernel/locking/mutex.c:893
 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:908
 blkdev_reread_part+0x1e/0x40 block/ioctl.c:192
 loop_reread_partitions+0x12f/0x1a0 drivers/block/loop.c:614
 loop_set_status+0x9ba/0xf60 drivers/block/loop.c:1156
 loop_set_status_compat+0x92/0xf0 drivers/block/loop.c:1506
 lo_compat_ioctl+0x114/0x140 drivers/block/loop.c:1534
 compat_blkdev_ioctl+0x3ba/0x1850 block/compat_ioctl.c:405
 C_SYSC_ioctl fs/compat_ioctl.c:1593 [inline]
 compat_SyS_ioctl+0x1d7/0x3290 fs/compat_ioctl.c:1540
 do_syscall_32_irqs_on arch/x86/entry/common.c:329 [inline]
 do_fast_syscall_32+0x3f2/0xf05 arch/x86/entry/common.c:391
 entry_SYSENTER_compat+0x51/0x60 arch/x86/entry/entry_64_compat.S:124
RIP: 0023:0xf7f4bc79
RSP: 002b:00000000ff90868c EFLAGS: 00000286 ORIG_RAX: 0000000000000036
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000004c02
RDX: 00000

All crashes (5665):
Manager	Time	Kernel	Commit	Syzkaller	Config	Log	Report	Syz repro	C repro	Maintainers
ci-upstream-kasan-gce	2017/09/25 13:28	upstream	e19b205be43d11bff638cad4487008c48d21c103	c26ea367cfa790e86800ac025638ad50f95b8287	.config	log	report	syz	C	["axboe@kernel.dk" "linux-block@vger.kernel.org" "linux-kernel@vger.kernel.org"]
ci-upstream-kasan-gce-386	2018/02/09 23:57	upstream	f9f1e414128ea58d8e848a0275db0f644c9e9f45	2b6b214cf2fc16447250192774f9c8e124793c50	.config	log	report	syz	C	["axboe@kernel.dk" "linux-block@vger.kernel.org" "linux-kernel@vger.kernel.org"]
ci-upstream-kasan-gce-386	2018/02/09 08:16	upstream	c0136321924dd338bb8fc5661c4b0e27441a8d04	9fb5ec4367f8816ba2297a39963778ad74d6f443	.config	log	report	syz	C	["axboe@kernel.dk" "linux-block@vger.kernel.org" "linux-kernel@vger.kernel.org"]
ci-upstream-kasan-gce-386	2017/12/19 23:51	upstream	ace52288edf0cb5e7a52b681f057f86224c49c27	af9163c76381c5363976d40392f9f6728d7a1dc9	.config	log	report	syz	C	["axboe@kernel.dk" "linux-block@vger.kernel.org" "linux-kernel@vger.kernel.org"]
ci-upstream-kasan-gce-386	2017/12/12 20:56	upstream	a638349bf6c29433b938141f99225b160551ff48	414a185f4d36140539d2783e5d7be02346c2cfbe	.config	log	report	syz	C	["axboe@kernel.dk" "linux-block@vger.kernel.org" "linux-kernel@vger.kernel.org"]
ci-upstream-kasan-gce-386	2017/11/15 04:15	upstream	894025f24bd028942da3e602b87d9f7223109b14	cf38de0018e34456cf066b70ca148ab502155672	.config	log	report	syz	C	["axboe@kernel.dk" "linux-block@vger.kernel.org" "linux-kernel@vger.kernel.org"]
ci-upstream-kasan-gce-386	2018/09/19 09:39	upstream	eba2d6b34a32bdc3585c5810633ec38f9472380c	7f125108ae79bbb6e5b3a4eedf3ab7fbcb845744	.config	log	report			["axboe@kernel.dk" "linux-block@vger.kernel.org" "linux-kernel@vger.kernel.org"]
ci-upstream-kasan-gce-386	2018/09/19 07:55	upstream	eba2d6b34a32bdc3585c5810633ec38f9472380c	7f125108ae79bbb6e5b3a4eedf3ab7fbcb845744	.config	log	report			["axboe@kernel.dk" "linux-block@vger.kernel.org" "linux-kernel@vger.kernel.org"]
ci-upstream-kasan-gce-386	2018/09/19 04:51	upstream	5211da9ca526a5adddee1ccd078e6e33a583ab36	7f125108ae79bbb6e5b3a4eedf3ab7fbcb845744	.config	log	report			["axboe@kernel.dk" "linux-block@vger.kernel.org" "linux-kernel@vger.kernel.org"]
ci-upstream-kasan-gce-386	2018/09/19 03:26	upstream	5211da9ca526a5adddee1ccd078e6e33a583ab36	7f125108ae79bbb6e5b3a4eedf3ab7fbcb845744	.config	log	report			["axboe@kernel.dk" "linux-block@vger.kernel.org" "linux-kernel@vger.kernel.org"]
ci-upstream-kasan-gce-386	2018/09/18 18:23	upstream	5211da9ca526a5adddee1ccd078e6e33a583ab36	7f125108ae79bbb6e5b3a4eedf3ab7fbcb845744	.config	log	report			["axboe@kernel.dk" "linux-block@vger.kernel.org" "linux-kernel@vger.kernel.org"]
ci-upstream-kasan-gce-386	2018/09/17 15:26	upstream	c0747ad363fff90c2edf490fc089e3ae0920b410	7f125108ae79bbb6e5b3a4eedf3ab7fbcb845744	.config	log	report			["axboe@kernel.dk" "linux-block@vger.kernel.org" "linux-kernel@vger.kernel.org"]
ci-upstream-kasan-gce-386	2018/09/17 14:13	upstream	c0747ad363fff90c2edf490fc089e3ae0920b410	7f125108ae79bbb6e5b3a4eedf3ab7fbcb845744	.config	log	report			["axboe@kernel.dk" "linux-block@vger.kernel.org" "linux-kernel@vger.kernel.org"]
ci-upstream-kasan-gce-386	2018/09/17 10:01	upstream	c0747ad363fff90c2edf490fc089e3ae0920b410	7f125108ae79bbb6e5b3a4eedf3ab7fbcb845744	.config	log	report			["axboe@kernel.dk" "linux-block@vger.kernel.org" "linux-kernel@vger.kernel.org"]
ci-upstream-kasan-gce-386	2018/09/15 23:25	upstream	3a5af36b6d0e4a42ec2a8552ace87edbe2a90ae4	a343a4003c23e2df136f9796f382ced37e9b7097	.config	log	report			["axboe@kernel.dk" "linux-block@vger.kernel.org" "linux-kernel@vger.kernel.org"]
ci-upstream-kasan-gce-386	2018/09/15 20:31	upstream	3a5af36b6d0e4a42ec2a8552ace87edbe2a90ae4	a343a4003c23e2df136f9796f382ced37e9b7097	.config	log	report			["axboe@kernel.dk" "linux-block@vger.kernel.org" "linux-kernel@vger.kernel.org"]
ci-upstream-kasan-gce-386	2018/09/15 12:12	upstream	090b75bcba62e8e0e43c8acdbc230d26c5b731dc	a343a4003c23e2df136f9796f382ced37e9b7097	.config	log	report			["axboe@kernel.dk" "linux-block@vger.kernel.org" "linux-kernel@vger.kernel.org"]
ci-upstream-kasan-gce-386	2018/09/13 21:16	upstream	54eda9df17f3215b9ed16629ee71ea07413efdaf	19e9088bb7b82fd5d7ece380a9495456350e3876	.config	log	report			["axboe@kernel.dk" "linux-block@vger.kernel.org" "linux-kernel@vger.kernel.org"]
ci-upstream-kasan-gce-386	2018/09/13 04:43	upstream	96eddb810b146e4d364e35f38dc11d16680c66eb	71907dafdbb47df824e03665e5b9fffa0dd07a9e	.config	log	report			["axboe@kernel.dk" "linux-block@vger.kernel.org" "linux-kernel@vger.kernel.org"]
ci-upstream-kasan-gce-386	2018/09/12 23:47	upstream	96eddb810b146e4d364e35f38dc11d16680c66eb	71907dafdbb47df824e03665e5b9fffa0dd07a9e	.config	log	report			["axboe@kernel.dk" "linux-block@vger.kernel.org" "linux-kernel@vger.kernel.org"]
ci-upstream-kasan-gce-386	2018/09/11 23:58	upstream	11da3a7f84f19c26da6f86af878298694ede0804	4ae17b1f4c91cfe2de0b2b51b67622dd0ac366af	.config	log	report			["axboe@kernel.dk" "linux-block@vger.kernel.org" "linux-kernel@vger.kernel.org"]
ci-upstream-kasan-gce-386	2018/09/11 04:37	upstream	11da3a7f84f19c26da6f86af878298694ede0804	8c88323f946850a91f696f8608dd2137247191b3	.config	log	report			["axboe@kernel.dk" "linux-block@vger.kernel.org" "linux-kernel@vger.kernel.org"]
ci-upstream-kasan-gce-386	2018/09/07 12:22	upstream	ca16eb342ebedbf3bb1d8450048fe428895b0b65	e30d3b524053cf8d688a1f486a5cde9b67d49e87	.config	log	report			["axboe@kernel.dk" "linux-block@vger.kernel.org" "linux-kernel@vger.kernel.org"]
ci-upstream-kasan-gce-386	2018/09/07 08:24	upstream	ca16eb342ebedbf3bb1d8450048fe428895b0b65	e30d3b524053cf8d688a1f486a5cde9b67d49e87	.config	log	report			["axboe@kernel.dk" "linux-block@vger.kernel.org" "linux-kernel@vger.kernel.org"]
ci-upstream-kasan-gce-386	2018/09/07 06:57	upstream	ca16eb342ebedbf3bb1d8450048fe428895b0b65	e30d3b524053cf8d688a1f486a5cde9b67d49e87	.config	log	report			["axboe@kernel.dk" "linux-block@vger.kernel.org" "linux-kernel@vger.kernel.org"]
ci-upstream-kasan-gce-386	2018/09/07 00:21	upstream	ca16eb342ebedbf3bb1d8450048fe428895b0b65	e30d3b524053cf8d688a1f486a5cde9b67d49e87	.config	log	report			["axboe@kernel.dk" "linux-block@vger.kernel.org" "linux-kernel@vger.kernel.org"]
ci-upstream-kasan-gce-386	2018/09/06 21:43	upstream	b36fdc6853a38a6f8749897a33435635019e0647	0bb7a7eb8e0958c6fbe2d69615b9fae4af88c8ee	.config	log	report			["axboe@kernel.dk" "linux-block@vger.kernel.org" "linux-kernel@vger.kernel.org"]
ci-upstream-kasan-gce-386	2018/09/06 08:45	upstream	b36fdc6853a38a6f8749897a33435635019e0647	873745f2ff183dcbc303a504683ccaa3a472a635	.config	log	report			["axboe@kernel.dk" "linux-block@vger.kernel.org" "linux-kernel@vger.kernel.org"]
ci-upstream-kasan-gce-386	2018/09/05 15:58	upstream	28619527b8a712590c93d0a9e24b4425b9376a8c	196410e4f5665d4d2bf6c818d06f1c8d03cfa8cc	.config	log	report			["axboe@kernel.dk" "linux-block@vger.kernel.org" "linux-kernel@vger.kernel.org"]
ci-upstream-kasan-gce-386	2018/09/05 05:55	upstream	28619527b8a712590c93d0a9e24b4425b9376a8c	a4718693a3d9fcabb02299b2ec07c19d8208c539	.config	log	report			["axboe@kernel.dk" "linux-block@vger.kernel.org" "linux-kernel@vger.kernel.org"]
ci-upstream-kasan-gce-386	2018/09/04 19:22	upstream	60c1f89241d49bacf71035470684a8d7b4bb46ea	a4718693a3d9fcabb02299b2ec07c19d8208c539	.config	log	report			["axboe@kernel.dk" "linux-block@vger.kernel.org" "linux-kernel@vger.kernel.org"]
ci-upstream-kasan-gce-386	2018/09/01 16:04	upstream	420f51f4ab6bce6e580390729fadb89c31123636	a4718693a3d9fcabb02299b2ec07c19d8208c539	.config	log	report			["axboe@kernel.dk" "linux-block@vger.kernel.org" "linux-kernel@vger.kernel.org"]
ci-upstream-kasan-gce-386	2018/09/01 11:52	upstream	420f51f4ab6bce6e580390729fadb89c31123636	a4718693a3d9fcabb02299b2ec07c19d8208c539	.config	log	report			["axboe@kernel.dk" "linux-block@vger.kernel.org" "linux-kernel@vger.kernel.org"]
ci-upstream-kasan-gce-386	2018/08/28 15:33	upstream	050cdc6c9501abcd64720b8cc3e7941efee9547d	7ef1de9ea4b02a8799b3a7f4b1d7b06a586b3f37	.config	log	report			["axboe@kernel.dk" "linux-block@vger.kernel.org" "linux-kernel@vger.kernel.org"]
ci-upstream-kasan-gce-386	2018/08/25 08:19	upstream	0519359784328bfa92bf0931bf0cff3b58c16932	9be5aa1d051dea559961cb42d3fa750ca40e2d5e	.config	log	report			["axboe@kernel.dk" "linux-block@vger.kernel.org" "linux-kernel@vger.kernel.org"]
ci-upstream-kasan-gce-386	2018/08/25 01:12	upstream	aa5b1054badb60191f6a09e7ef65beacf837c5d4	9b0f5c758d7dad40a15368d6d71ea4b7be1948d1	.config	log	report			["axboe@kernel.dk" "linux-block@vger.kernel.org" "linux-kernel@vger.kernel.org"]
ci-upstream-kasan-gce-386	2018/08/24 14:14	upstream	33e17876ea4edcd7f5c01efa78e8d02889261abf	95b5c82b28c3107383df2cd38d9af8c7984bd31c	.config	log	report			["axboe@kernel.dk" "linux-block@vger.kernel.org" "linux-kernel@vger.kernel.org"]
ci-upstream-kasan-gce-386	2018/08/23 19:02	upstream	815f0ddb346c196018d4d8f8f55c12b83da1de3f	95b5c82b28c3107383df2cd38d9af8c7984bd31c	.config	log	report			["axboe@kernel.dk" "linux-block@vger.kernel.org" "linux-kernel@vger.kernel.org"]
ci-upstream-kasan-gce-386	2018/08/23 17:50	upstream	815f0ddb346c196018d4d8f8f55c12b83da1de3f	95b5c82b28c3107383df2cd38d9af8c7984bd31c	.config	log	report			["axboe@kernel.dk" "linux-block@vger.kernel.org" "linux-kernel@vger.kernel.org"]
ci-upstream-kasan-gce-386	2018/08/23 06:53	upstream	899fbc33fd775b9dfa363db28f322272920a2196	95b5c82b28c3107383df2cd38d9af8c7984bd31c	.config	log	report			["axboe@kernel.dk" "linux-block@vger.kernel.org" "linux-kernel@vger.kernel.org"]
ci-upstream-kasan-gce-386	2018/08/22 09:29	upstream	0214f46b3a0383d6e33c297e7706216b6a550e4b	95b5c82b28c3107383df2cd38d9af8c7984bd31c	.config	log	report			["axboe@kernel.dk" "linux-block@vger.kernel.org" "linux-kernel@vger.kernel.org"]
ci-upstream-kasan-gce-386	2018/08/19 14:48	upstream	08b5fa819970c318e58ab638f497633c25971813	2dc4378f0225c80d2755f7531ad0de4c2044727a	.config	log	report			["axboe@kernel.dk" "linux-block@vger.kernel.org" "linux-kernel@vger.kernel.org"]
ci-upstream-kasan-gce-386	2018/08/18 21:17	upstream	a18d783fedfe6f9b720afe901db9501ce116ed81	de20bcbb68a06e9589f4ad2bb162aa1feed0c5c9	.config	log	report			["axboe@kernel.dk" "linux-block@vger.kernel.org" "linux-kernel@vger.kernel.org"]
ci-upstream-kasan-gce-386	2018/08/18 17:51	upstream	1f7a4c73a739a63b3f108d8eda6f947fdc70dd65	db1858f6b9dec7ff54adf144f378679b405b8509	.config	log	report			["axboe@kernel.dk" "linux-block@vger.kernel.org" "linux-kernel@vger.kernel.org"]
ci-upstream-kasan-gce-386	2018/08/17 04:07	upstream	5c60a7389d795e001c8748b458eb76e3a5b6008c	9ccc1d4565436890480aea12b6ae347384b2d1ab	.config	log	report			["axboe@kernel.dk" "linux-block@vger.kernel.org" "linux-kernel@vger.kernel.org"]
ci-upstream-kasan-gce-386	2018/08/14 20:08	upstream	10f3e23f07cb0c20f9bcb77a5b5a7eb2a1b2a2fe	5084a6252d15d19bb1cdb8c2bba86a6debbd3c16	.config	log	report			["axboe@kernel.dk" "linux-block@vger.kernel.org" "linux-kernel@vger.kernel.org"]
ci-upstream-kasan-gce-386	2018/08/14 11:19	upstream	7796916146b8c34cbbef66470ab8b5b28cf47e83	7a88b14122b5b70ed04bcd75932f411256e1662b	.config	log	report			["axboe@kernel.dk" "linux-block@vger.kernel.org" "linux-kernel@vger.kernel.org"]
ci-upstream-kasan-gce-386	2018/08/13 19:20	upstream	94710cac0ef4ee177a63b5227664b38c95bbf703	7a88b14122b5b70ed04bcd75932f411256e1662b	.config	log	report			["axboe@kernel.dk" "linux-block@vger.kernel.org" "linux-kernel@vger.kernel.org"]
ci-upstream-kasan-gce-386	2018/08/13 04:49	upstream	d6dd6431591b2af8580cd2b57f501352222edb4f	7a88b14122b5b70ed04bcd75932f411256e1662b	.config	log	report			["axboe@kernel.dk" "linux-block@vger.kernel.org" "linux-kernel@vger.kernel.org"]
ci-upstream-kasan-gce-386	2018/08/12 21:33	upstream	d6dd6431591b2af8580cd2b57f501352222edb4f	7a88b14122b5b70ed04bcd75932f411256e1662b	.config	log	report			["axboe@kernel.dk" "linux-block@vger.kernel.org" "linux-kernel@vger.kernel.org"]