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s10-20020a056808208a00b003ae11eeb66fmr10438498oiw.3.1696966722911; Tue, 10 Oct 2023 12:38:42 -0700 (PDT) Date: Tue, 10 Oct 2023 12:38:42 -0700 In-Reply-To: <000000000000cc15ee05ed0ca085@google.com> X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <000000000000b70395060761da97@google.com> Subject: Re: [syzbot] [reiserfs?] possible deadlock in filename_create From: syzbot To: linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, reiserfs-devel@vger.kernel.org, syzkaller-bugs@googlegroups.com Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org syzbot has found a reproducer for the following issue on: HEAD commit: 19af4a4ed414 Merge branch 'for-next/core', remote-tracking.. git tree: git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci console output: https://syzkaller.appspot.com/x/log.txt?x=15da0ec9680000 kernel config: https://syzkaller.appspot.com/x/.config?x=80eedef55cd21fa4 dashboard link: https://syzkaller.appspot.com/bug?extid=95cb07e3840546a4827b compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40 userspace arch: arm64 syz repro: https://syzkaller.appspot.com/x/repro.syz?x=11957c65680000 C reproducer: https://syzkaller.appspot.com/x/repro.c?x=1304e6ba680000 Downloadable assets: disk image: https://storage.googleapis.com/syzbot-assets/702d996331e0/disk-19af4a4e.raw.xz vmlinux: https://storage.googleapis.com/syzbot-assets/2a48ce0aeb32/vmlinux-19af4a4e.xz kernel image: https://storage.googleapis.com/syzbot-assets/332eb4a803d2/Image-19af4a4e.gz.xz mounted in repro #1: https://storage.googleapis.com/syzbot-assets/a4536cf3a09f/mount_0.gz mounted in repro #2: https://storage.googleapis.com/syzbot-assets/88a36e03ffba/mount_3.gz IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+95cb07e3840546a4827b@syzkaller.appspotmail.com REISERFS (device loop0): Created .reiserfs_priv - reserved for xattr storage. ====================================================== WARNING: possible circular locking dependency detected 6.6.0-rc4-syzkaller-g19af4a4ed414 #0 Not tainted ------------------------------------------------------ syz-executor324/6098 is trying to acquire lock: ffff0000dd376640 (&type->i_mutex_dir_key#6/1){+.+.}-{3:3}, at: inode_lock_nested include/linux/fs.h:837 [inline] ffff0000dd376640 (&type->i_mutex_dir_key#6/1){+.+.}-{3:3}, at: filename_create+0x204/0x468 fs/namei.c:3889 but task is already holding lock: ffff0000d494e410 (sb_writers#8){.+.+}-{0:0}, at: mnt_want_write+0x44/0x9c fs/namespace.c:403 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #2 (sb_writers#8){.+.+}-{0:0}: percpu_down_read include/linux/percpu-rwsem.h:51 [inline] __sb_start_write include/linux/fs.h:1571 [inline] sb_start_write+0x60/0x2ec include/linux/fs.h:1646 mnt_want_write_file+0x64/0x1e8 fs/namespace.c:447 reiserfs_ioctl+0x188/0x42c fs/reiserfs/ioctl.c:103 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:871 [inline] __se_sys_ioctl fs/ioctl.c:857 [inline] __arm64_sys_ioctl+0x14c/0x1c8 fs/ioctl.c:857 __invoke_syscall arch/arm64/kernel/syscall.c:37 [inline] invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:51 el0_svc_common+0x130/0x23c arch/arm64/kernel/syscall.c:136 do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:155 el0_svc+0x58/0x16c arch/arm64/kernel/entry-common.c:678 el0t_64_sync_handler+0x84/0xfc arch/arm64/kernel/entry-common.c:696 el0t_64_sync+0x190/0x194 arch/arm64/kernel/entry.S:595 -> #1 (&sbi->lock){+.+.}-{3:3}: __mutex_lock_common+0x190/0x21a0 kernel/locking/mutex.c:603 __mutex_lock kernel/locking/mutex.c:747 [inline] mutex_lock_nested+0x2c/0x38 kernel/locking/mutex.c:799 reiserfs_write_lock+0x7c/0xe8 fs/reiserfs/lock.c:27 reiserfs_lookup+0x128/0x45c fs/reiserfs/namei.c:364 lookup_one_qstr_excl+0x108/0x230 fs/namei.c:1608 filename_create+0x230/0x468 fs/namei.c:3890 do_mkdirat+0xac/0x610 fs/namei.c:4135 __do_sys_mkdirat fs/namei.c:4158 [inline] __se_sys_mkdirat fs/namei.c:4156 [inline] __arm64_sys_mkdirat+0x90/0xa8 fs/namei.c:4156 __invoke_syscall arch/arm64/kernel/syscall.c:37 [inline] invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:51 el0_svc_common+0x130/0x23c arch/arm64/kernel/syscall.c:136 do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:155 el0_svc+0x58/0x16c arch/arm64/kernel/entry-common.c:678 el0t_64_sync_handler+0x84/0xfc arch/arm64/kernel/entry-common.c:696 el0t_64_sync+0x190/0x194 arch/arm64/kernel/entry.S:595 -> #0 ( &type->i_mutex_dir_key#6/1){+.+.}-{3:3}: check_prev_add kernel/locking/lockdep.c:3134 [inline] check_prevs_add kernel/locking/lockdep.c:3253 [inline] validate_chain kernel/locking/lockdep.c:3868 [inline] __lock_acquire+0x3370/0x75e8 kernel/locking/lockdep.c:5136 lock_acquire+0x23c/0x71c kernel/locking/lockdep.c:5753 down_write_nested+0x58/0xcc kernel/locking/rwsem.c:1689 inode_lock_nested include/linux/fs.h:837 [inline] filename_create+0x204/0x468 fs/namei.c:3889 do_mkdirat+0xac/0x610 fs/namei.c:4135 __do_sys_mkdirat fs/namei.c:4158 [inline] __se_sys_mkdirat fs/namei.c:4156 [inline] __arm64_sys_mkdirat+0x90/0xa8 fs/namei.c:4156 __invoke_syscall arch/arm64/kernel/syscall.c:37 [inline] invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:51 el0_svc_common+0x130/0x23c arch/arm64/kernel/syscall.c:136 do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:155 el0_svc+0x58/0x16c arch/arm64/kernel/entry-common.c:678 el0t_64_sync_handler+0x84/0xfc arch/arm64/kernel/entry-common.c:696 el0t_64_sync+0x190/0x194 arch/arm64/kernel/entry.S:595 other info that might help us debug this: Chain exists of: &type->i_mutex_dir_key#6/1 --> &sbi->lock --> sb_writers#8 Possible unsafe locking scenario: CPU0 CPU1 ---- ---- rlock(sb_writers#8); lock(&sbi->lock); lock(sb_writers#8); lock(&type->i_mutex_dir_key#6/1); *** DEADLOCK *** 1 lock held by syz-executor324/6098: #0: ffff0000d494e410 (sb_writers#8){.+.+}-{0:0}, at: mnt_want_write+0x44/0x9c fs/namespace.c:403 stack backtrace: CPU: 1 PID: 6098 Comm: syz-executor324 Not tainted 6.6.0-rc4-syzkaller-g19af4a4ed414 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/06/2023 Call trace: dump_backtrace+0x1b8/0x1e4 arch/arm64/kernel/stacktrace.c:233 show_stack+0x2c/0x44 arch/arm64/kernel/stacktrace.c:240 __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0xd0/0x124 lib/dump_stack.c:106 dump_stack+0x1c/0x28 lib/dump_stack.c:113 print_circular_bug+0x150/0x1b8 kernel/locking/lockdep.c:2060 check_noncircular+0x310/0x404 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:3868 [inline] __lock_acquire+0x3370/0x75e8 kernel/locking/lockdep.c:5136 lock_acquire+0x23c/0x71c kernel/locking/lockdep.c:5753 down_write_nested+0x58/0xcc kernel/locking/rwsem.c:1689 inode_lock_nested include/linux/fs.h:837 [inline] filename_create+0x204/0x468 fs/namei.c:3889 do_mkdirat+0xac/0x610 fs/namei.c:4135 __do_sys_mkdirat fs/namei.c:4158 [inline] __se_sys_mkdirat fs/namei.c:4156 [inline] __arm64_sys_mkdirat+0x90/0xa8 fs/namei.c:4156 __invoke_syscall arch/arm64/kernel/syscall.c:37 [inline] invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:51 el0_svc_common+0x130/0x23c arch/arm64/kernel/syscall.c:136 do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:155 el0_svc+0x58/0x16c arch/arm64/kernel/entry-common.c:678 el0t_64_sync_handler+0x84/0xfc arch/arm64/kernel/entry-common.c:696 el0t_64_sync+0x190/0x194 arch/arm64/kernel/entry.S:595 --- 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.