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[49.195.9.235]) by smtp.gmail.com with ESMTPSA id d9443c01a7336-215f8e66ba7sm128835425ad.100.2024.12.12.15.40.45 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 12 Dec 2024 15:40:45 -0800 (PST) Received: from dave by dread.disaster.area with local (Exim 4.98) (envelope-from ) id 1tLsnT-00000009zsS-3Zih; Fri, 13 Dec 2024 10:40:43 +1100 Date: Fri, 13 Dec 2024 10:40:43 +1100 From: Dave Chinner To: syzbot Cc: adilger.kernel@dilger.ca, linux-ext4@vger.kernel.org, linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com, tytso@mit.edu Subject: Re: [syzbot] [ext4?] possible deadlock in ext4_truncate Message-ID: References: <6753e03f.050a0220.a30f1.0152.GAE@google.com> Precedence: bulk X-Mailing-List: linux-ext4@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <6753e03f.050a0220.a30f1.0152.GAE@google.com> On Fri, Dec 06, 2024 at 09:42:23PM -0800, syzbot wrote: > Hello, > > syzbot found the following issue on: > > HEAD commit: cdd30ebb1b9f module: Convert symbol namespace to string li.. > git tree: upstream > console output: https://syzkaller.appspot.com/x/log.txt?x=15898330580000 > kernel config: https://syzkaller.appspot.com/x/.config?x=50c7a61469ce77e7 > dashboard link: https://syzkaller.appspot.com/bug?extid=449c80b8f4946f26184b > compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40 > > Unfortunately, I don't have any reproducer for this issue yet. > > Downloadable assets: > disk image: https://storage.googleapis.com/syzbot-assets/658bd206f462/disk-cdd30ebb.raw.xz > vmlinux: https://storage.googleapis.com/syzbot-assets/12cb86080d87/vmlinux-cdd30ebb.xz > kernel image: https://storage.googleapis.com/syzbot-assets/5181aac6587a/bzImage-cdd30ebb.xz > > IMPORTANT: if you fix the issue, please add the following tag to the commit: > Reported-by: syzbot+449c80b8f4946f26184b@syzkaller.appspotmail.com > > ====================================================== > WARNING: possible circular locking dependency detected > 6.13.0-rc1-syzkaller-00002-gcdd30ebb1b9f #0 Not tainted > ------------------------------------------------------ > syz-executor/11503 is trying to acquire lock: > ffff88807abcdbb0 (&ei->i_data_sem){++++}-{4:4}, at: ext4_truncate+0x994/0x11c0 fs/ext4/inode.c:4212 > > but task is already holding lock: > ffff888034d3a610 (sb_internal){++++}-{0:0}, at: __sb_start_write include/linux/fs.h:1725 [inline] > ffff888034d3a610 (sb_internal){++++}-{0:0}, at: sb_start_intwrite include/linux/fs.h:1908 [inline] > ffff888034d3a610 (sb_internal){++++}-{0:0}, at: ext4_evict_inode+0x2f4/0xf50 fs/ext4/inode.c:217 > > which lock already depends on the new lock. > > > the existing dependency chain (in reverse order) is: > > -> #7 (sb_internal){++++}-{0:0}: > lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5849 > percpu_down_write+0x54/0x310 kernel/locking/percpu-rwsem.c:229 > sb_wait_write fs/super.c:1910 [inline] > freeze_super+0x7cc/0xee0 fs/super.c:2118 > fs_bdev_freeze+0x1ac/0x320 fs/super.c:1484 > bdev_freeze+0xd8/0x220 block/bdev.c:257 > ext4_force_shutdown+0x319/0x550 fs/ext4/ioctl.c:822 > ext4_ioctl_shutdown fs/ext4/ioctl.c:857 [inline] > __ext4_ioctl fs/ext4/ioctl.c:1580 [inline] > ext4_ioctl+0x2145/0x58d0 fs/ext4/ioctl.c:1619 > vfs_ioctl fs/ioctl.c:51 [inline] > __do_sys_ioctl fs/ioctl.c:906 [inline] > __se_sys_ioctl+0xf7/0x170 fs/ioctl.c:892 > do_syscall_x64 arch/x86/entry/common.c:52 [inline] > do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83 > entry_SYSCALL_64_after_hwframe+0x77/0x7f > > -> #6 (sb_pagefaults){++++}-{0:0}: > lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5849 > percpu_down_read+0x44/0x1b0 include/linux/percpu-rwsem.h:51 > __sb_start_write include/linux/fs.h:1725 [inline] > sb_start_pagefault include/linux/fs.h:1890 [inline] > ext4_page_mkwrite+0x1ef/0xdf0 fs/ext4/inode.c:6158 > do_page_mkwrite+0x19a/0x480 mm/memory.c:3176 > do_shared_fault mm/memory.c:5398 [inline] > do_fault mm/memory.c:5460 [inline] > do_pte_missing mm/memory.c:3979 [inline] > handle_pte_fault+0x1235/0x68a0 mm/memory.c:5801 > __handle_mm_fault mm/memory.c:5944 [inline] > handle_mm_fault+0x1106/0x1bb0 mm/memory.c:6112 > do_user_addr_fault arch/x86/mm/fault.c:1389 [inline] > handle_page_fault arch/x86/mm/fault.c:1481 [inline] > exc_page_fault+0x2b9/0x8b0 arch/x86/mm/fault.c:1539 > asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:623 > > -> #5 (&mm->mmap_lock){++++}-{4:4}: > lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5849 > __might_fault+0xc6/0x120 mm/memory.c:6751 > _inline_copy_from_user include/linux/uaccess.h:162 [inline] > _copy_from_user+0x2a/0xc0 lib/usercopy.c:18 > copy_from_user include/linux/uaccess.h:212 [inline] > __blk_trace_setup kernel/trace/blktrace.c:626 [inline] > blk_trace_ioctl+0x1ad/0x9a0 kernel/trace/blktrace.c:740 > blkdev_ioctl+0x40c/0x6a0 block/ioctl.c:682 > vfs_ioctl fs/ioctl.c:51 [inline] > __do_sys_ioctl fs/ioctl.c:906 [inline] > __se_sys_ioctl+0xf7/0x170 fs/ioctl.c:892 > do_syscall_x64 arch/x86/entry/common.c:52 [inline] > do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83 > entry_SYSCALL_64_after_hwframe+0x77/0x7f #syz dup: possible deadlock in xfs_vn_update_time -- Dave Chinner david@fromorbit.com