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List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Received: by 2002:a05:6638:8906:b0:4b9:2bc3:46ba with SMTP id 8926c6da1cb9f-4b9efc00420mr263967173.3.1719272485994; Mon, 24 Jun 2024 16:41:25 -0700 (PDT) Date: Mon, 24 Jun 2024 16:41:25 -0700 In-Reply-To: <0000000000007de4c3061ba8ca57@google.com> X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <000000000000cccfa2061bab512c@google.com> Subject: Re: [syzbot] [kernfs?] possible deadlock in __kernfs_remove From: syzbot To: a.sangwan@samsung.com, dan.j.williams@intel.com, dave.jiang@intel.com, dirk.behme@de.bosch.com, gregkh@linuxfoundation.org, ira.weiny@intel.com, linux-kernel@vger.kernel.org, namjae.jeon@samsung.com, penguin-kernel@i-love.sakura.ne.jp, peterz@infradead.org, syzkaller-bugs@googlegroups.com, tj@kernel.org, vishal.l.verma@intel.com Content-Type: text/plain; charset="UTF-8" syzbot has found a reproducer for the following issue on: HEAD commit: 626737a5791b Merge tag 'pinctrl-v6.10-2' of git://git.kern.. git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=12b594ae980000 kernel config: https://syzkaller.appspot.com/x/.config?x=d6b9ee98d841760c dashboard link: https://syzkaller.appspot.com/bug?extid=4762dd74e32532cda5ff compiler: gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40 syz repro: https://syzkaller.appspot.com/x/repro.syz?x=14f21cea980000 C reproducer: https://syzkaller.appspot.com/x/repro.c?x=14c4963e980000 Downloadable assets: disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/7bc7510fe41f/non_bootable_disk-626737a5.raw.xz vmlinux: https://storage.googleapis.com/syzbot-assets/1cffeb16f347/vmlinux-626737a5.xz kernel image: https://storage.googleapis.com/syzbot-assets/b20910e32f0e/bzImage-626737a5.xz mounted in repro: https://storage.googleapis.com/syzbot-assets/67438b2787f0/mount_0.gz IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+4762dd74e32532cda5ff@syzkaller.appspotmail.com Buffer I/O error on dev loop0p1, logical block 8, async page read ====================================================== WARNING: possible circular locking dependency detected 6.10.0-rc5-syzkaller-00012-g626737a5791b #0 Not tainted ------------------------------------------------------ udevd/5224 is trying to acquire lock: ffff888029878a58 (kn->active#5){++++}-{0:0}, at: __kernfs_remove+0x281/0x670 fs/kernfs/dir.c:1486 but task is already holding lock: ffff8880219b84c8 (&disk->open_mutex){+.+.}-{3:3}, at: bdev_open+0x41a/0xe50 block/bdev.c:897 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #2 (&disk->open_mutex){+.+.}-{3:3}: __mutex_lock_common kernel/locking/mutex.c:608 [inline] __mutex_lock+0x175/0x9c0 kernel/locking/mutex.c:752 bdev_open+0x41a/0xe50 block/bdev.c:897 bdev_file_open_by_dev block/bdev.c:1011 [inline] bdev_file_open_by_dev+0x17d/0x210 block/bdev.c:986 disk_scan_partitions+0x1ed/0x320 block/genhd.c:367 device_add_disk+0xe97/0x1250 block/genhd.c:510 pmem_attach_disk+0x9fe/0x1400 drivers/nvdimm/pmem.c:578 nd_pmem_probe+0x1a9/0x1f0 drivers/nvdimm/pmem.c:651 nvdimm_bus_probe+0x169/0x5d0 drivers/nvdimm/bus.c:91 call_driver_probe drivers/base/dd.c:578 [inline] really_probe+0x23e/0xa90 drivers/base/dd.c:656 __driver_probe_device+0x1de/0x440 drivers/base/dd.c:798 driver_probe_device+0x4c/0x1b0 drivers/base/dd.c:828 __driver_attach+0x283/0x580 drivers/base/dd.c:1214 bus_for_each_dev+0x13c/0x1d0 drivers/base/bus.c:368 bus_add_driver+0x2e9/0x690 drivers/base/bus.c:673 driver_register+0x15c/0x4b0 drivers/base/driver.c:246 __nd_driver_register+0x103/0x1a0 drivers/nvdimm/bus.c:619 do_one_initcall+0x128/0x700 init/main.c:1267 do_initcall_level init/main.c:1329 [inline] do_initcalls init/main.c:1345 [inline] do_basic_setup init/main.c:1364 [inline] kernel_init_freeable+0x69d/0xca0 init/main.c:1578 kernel_init+0x1c/0x2b0 init/main.c:1467 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 -> #1 (&nvdimm_namespace_key){+.+.}-{3:3}: __mutex_lock_common kernel/locking/mutex.c:608 [inline] __mutex_lock+0x175/0x9c0 kernel/locking/mutex.c:752 device_lock include/linux/device.h:1009 [inline] uevent_show+0x188/0x3b0 drivers/base/core.c:2743 dev_attr_show+0x53/0xe0 drivers/base/core.c:2437 sysfs_kf_seq_show+0x23e/0x410 fs/sysfs/file.c:59 seq_read_iter+0x4fa/0x12c0 fs/seq_file.c:230 kernfs_fop_read_iter+0x41a/0x590 fs/kernfs/file.c:279 new_sync_read fs/read_write.c:395 [inline] vfs_read+0x869/0xbd0 fs/read_write.c:476 ksys_read+0x12f/0x260 fs/read_write.c:619 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f -> #0 (kn->active#5){++++}-{0:0}: check_prev_add kernel/locking/lockdep.c:3134 [inline] check_prevs_add kernel/locking/lockdep.c:3253 [inline] validate_chain kernel/locking/lockdep.c:3869 [inline] __lock_acquire+0x2478/0x3b30 kernel/locking/lockdep.c:5137 lock_acquire kernel/locking/lockdep.c:5754 [inline] lock_acquire+0x1b1/0x560 kernel/locking/lockdep.c:5719 kernfs_drain+0x48f/0x590 fs/kernfs/dir.c:500 __kernfs_remove+0x281/0x670 fs/kernfs/dir.c:1486 kernfs_remove_by_name_ns+0xb2/0x130 fs/kernfs/dir.c:1694 sysfs_remove_file include/linux/sysfs.h:773 [inline] device_remove_file drivers/base/core.c:3061 [inline] device_remove_file drivers/base/core.c:3057 [inline] device_del+0x381/0x9f0 drivers/base/core.c:3866 drop_partition+0x109/0x1c0 block/partitions/core.c:273 bdev_disk_changed+0x24d/0x14f0 block/partitions/core.c:664 blkdev_get_whole+0x187/0x290 block/bdev.c:700 bdev_open+0x2c7/0xe50 block/bdev.c:909 blkdev_open+0x17b/0x1f0 block/fops.c:615 do_dentry_open+0x910/0x1930 fs/open.c:955 do_open fs/namei.c:3650 [inline] path_openat+0x1e3a/0x29f0 fs/namei.c:3807 do_filp_open+0x1dc/0x430 fs/namei.c:3834 do_sys_openat2+0x17a/0x1e0 fs/open.c:1405 do_sys_open fs/open.c:1420 [inline] __do_sys_openat fs/open.c:1436 [inline] __se_sys_openat fs/open.c:1431 [inline] __x64_sys_openat+0x175/0x210 fs/open.c:1431 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f other info that might help us debug this: Chain exists of: kn->active#5 --> &nvdimm_namespace_key --> &disk->open_mutex Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&disk->open_mutex); lock(&nvdimm_namespace_key); lock(&disk->open_mutex); lock(kn->active#5); *** DEADLOCK *** 1 lock held by udevd/5224: #0: ffff8880219b84c8 (&disk->open_mutex){+.+.}-{3:3}, at: bdev_open+0x41a/0xe50 block/bdev.c:897 stack backtrace: CPU: 2 PID: 5224 Comm: udevd Not tainted 6.10.0-rc5-syzkaller-00012-g626737a5791b #0 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:114 check_noncircular+0x31a/0x400 kernel/locking/lockdep.c:2187 check_prev_add kernel/locking/lockdep.c:3134 [inline] check_prevs_add kernel/locking/lockdep.c:3253 [inline] validate_chain kernel/locking/lockdep.c:3869 [inline] __lock_acquire+0x2478/0x3b30 kernel/locking/lockdep.c:5137 lock_acquire kernel/locking/lockdep.c:5754 [inline] lock_acquire+0x1b1/0x560 kernel/locking/lockdep.c:5719 kernfs_drain+0x48f/0x590 fs/kernfs/dir.c:500 __kernfs_remove+0x281/0x670 fs/kernfs/dir.c:1486 kernfs_remove_by_name_ns+0xb2/0x130 fs/kernfs/dir.c:1694 sysfs_remove_file include/linux/sysfs.h:773 [inline] device_remove_file drivers/base/core.c:3061 [inline] device_remove_file drivers/base/core.c:3057 [inline] device_del+0x381/0x9f0 drivers/base/core.c:3866 drop_partition+0x109/0x1c0 block/partitions/core.c:273 bdev_disk_changed+0x24d/0x14f0 block/partitions/core.c:664 blkdev_get_whole+0x187/0x290 block/bdev.c:700 bdev_open+0x2c7/0xe50 block/bdev.c:909 blkdev_open+0x17b/0x1f0 block/fops.c:615 do_dentry_open+0x910/0x1930 fs/open.c:955 do_open fs/namei.c:3650 [inline] path_openat+0x1e3a/0x29f0 fs/namei.c:3807 do_filp_open+0x1dc/0x430 fs/namei.c:3834 do_sys_openat2+0x17a/0x1e0 fs/open.c:1405 do_sys_open fs/open.c:1420 [inline] __do_sys_openat fs/open.c:1436 [inline] __se_sys_openat fs/open.c:1431 [inline] __x64_sys_openat+0x175/0x210 fs/open.c:1431 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fc33c7979a4 Code: 24 20 48 8d 44 24 30 48 89 44 24 28 64 8b 04 25 18 00 00 00 85 c0 75 2c 44 89 e2 48 89 ee bf 9c ff ff ff b8 01 01 00 00 0f 05 <48> 3d 00 f0 ff ff 76 60 48 8b 15 55 a4 0d 00 f7 d8 64 89 02 48 83 RSP: 002b:00007ffc38f9eb40 EFLAGS: 00000246 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 00005569ecaa5ab0 RCX: 00007fc33c7979a4 RDX: 00000000000a0800 RSI: 00005569eca8bfb0 RDI: 00000000ffffff9c RBP: 00005569eca8bfb0 R08: 00000000ffffffff R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000000a0800 R13: 00005569ecaa7820 R14: 0000000000000001 R15: 00005569eca722c0 blk_print_req_error: 53 callbacks suppressed I/O error, dev loop0, sector 0 op 0x0:(READ) flags 0x80700 phys_seg 1 prio class 0 udevd[5224]: inotify_add_watch(7, /dev/loop0p1, 10) failed: No such file or directory udevd[5224]: inotify_add_watch(7, /dev/loop0p1, 10) failed: No such file or directory I/O error, dev loop0, sector 0 op 0x0:(READ) flags 0x80700 phys_seg 1 prio class 0 udevd[5224]: inotify_add_watch(7, /dev/loop0p1, 10) failed: No such file or directory I/O error, dev loop0, sector 0 op 0x0:(READ) flags 0x80700 phys_seg 1 prio class 0 udevd[5224]: inotify_add_watch(7, /dev/loop0p1, 10) failed: No such file or directory I/O error, dev loop0, sector 0 op 0x0:(READ) flags 0x80700 phys_seg 1 prio class 0 I/O error, dev loop0, sector 0 op 0x0:(READ) flags 0x80700 phys_seg 1 prio class 0 I/O error, dev loop0, sector 0 op 0x0:(READ) flags 0x80700 phys_seg 1 prio class 0 I/O error, dev loop0, sector 108 op 0x0:(READ) flags 0x80700 phys_seg 1 prio class 0 Buffer I/O error on dev loop0p1, logical block 8, async page read udevd[5224]: inotify_add_watch(7, /dev/loop0p1, 10) failed: No such file or directory blk_print_req_error: 138 callbacks suppressed I/O error, dev loop0, sector 108 op 0x0:(READ) flags 0x80700 phys_seg 1 prio class 0 udevd[5224]: inotify_add_watch(7, /dev/loop0p1, 10) failed: No such file or directory udevd[5224]: inotify_add_watch(7, /dev/loop0p1, 10) failed: No such file or directory --- If you want syzbot to run the reproducer, reply with: #syz test: git://repo/address.git branch-or-commit-hash If you attach or paste a git patch, syzbot will apply it before testing.