xt_socket: unknown flags 0x2 xt_socket: unknown flags 0x2 ====================================================== WARNING: possible circular locking dependency detected 4.19.198-syzkaller #0 Not tainted ------------------------------------------------------ syz-executor.3/3534 is trying to acquire lock: 00000000cdca1346 (&sig->cred_guard_mutex){+.+.}, at: do_io_accounting fs/proc/base.c:2750 [inline] 00000000cdca1346 (&sig->cred_guard_mutex){+.+.}, at: proc_tid_io_accounting+0x184/0x2b0 fs/proc/base.c:2793 but task is already holding lock: 00000000e52eeead (&p->lock){+.+.}, at: seq_read+0x6b/0x11c0 fs/seq_file.c:164 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #3 (&p->lock){+.+.}: seq_read+0x6b/0x11c0 fs/seq_file.c:164 proc_reg_read+0x1bd/0x2d0 fs/proc/inode.c:231 do_loop_readv_writev fs/read_write.c:701 [inline] do_loop_readv_writev fs/read_write.c:688 [inline] do_iter_read+0x471/0x630 fs/read_write.c:925 vfs_readv+0xe5/0x150 fs/read_write.c:987 kernel_readv fs/splice.c:362 [inline] default_file_splice_read+0x457/0xa00 fs/splice.c:417 do_splice_to+0x10e/0x160 fs/splice.c:881 splice_direct_to_actor+0x2b9/0x8d0 fs/splice.c:959 do_splice_direct+0x1a7/0x270 fs/splice.c:1068 do_sendfile+0x550/0xc30 fs/read_write.c:1447 IPVS: ftp: loaded support on port[0] = 21 __do_sys_sendfile64 fs/read_write.c:1508 [inline] __se_sys_sendfile64+0x147/0x160 fs/read_write.c:1494 do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe -> #2 (sb_writers#3){.+.+}: sb_start_write include/linux/fs.h:1579 [inline] mnt_want_write+0x3a/0xb0 fs/namespace.c:360 ovl_create_object+0x96/0x290 fs/overlayfs/dir.c:600 lookup_open+0x893/0x1a20 fs/namei.c:3235 do_last fs/namei.c:3327 [inline] path_openat+0x1094/0x2df0 fs/namei.c:3537 do_filp_open+0x18c/0x3f0 fs/namei.c:3567 do_sys_open+0x3b3/0x520 fs/open.c:1085 do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe -> #1 (&ovl_i_mutex_dir_key[depth]){++++}: IPVS: ftp: loaded support on port[0] = 21 inode_lock_shared include/linux/fs.h:758 [inline] do_last fs/namei.c:3326 [inline] path_openat+0x17ec/0x2df0 fs/namei.c:3537 do_filp_open+0x18c/0x3f0 fs/namei.c:3567 xt_socket: unknown flags 0x2 do_open_execat+0x11d/0x5b0 fs/exec.c:853 __do_execve_file+0x1a8b/0x2360 fs/exec.c:1770 xt_socket: unknown flags 0x2 do_execveat_common fs/exec.c:1879 [inline] do_execve+0x35/0x50 fs/exec.c:1896 __do_sys_execve fs/exec.c:1977 [inline] __se_sys_execve fs/exec.c:1972 [inline] __x64_sys_execve+0x7c/0xa0 fs/exec.c:1972 do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe -> #0 (&sig->cred_guard_mutex){+.+.}: __mutex_lock_common kernel/locking/mutex.c:938 [inline] __mutex_lock+0xd7/0x1200 kernel/locking/mutex.c:1083 do_io_accounting fs/proc/base.c:2750 [inline] proc_tid_io_accounting+0x184/0x2b0 fs/proc/base.c:2793 proc_single_show+0xeb/0x170 fs/proc/base.c:755 seq_read+0x4e0/0x11c0 fs/seq_file.c:232 __vfs_read+0xf7/0x750 fs/read_write.c:416 vfs_read+0x194/0x3c0 fs/read_write.c:452 ksys_read+0x12b/0x2a0 fs/read_write.c:579 do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe other info that might help us debug this: Chain exists of: &sig->cred_guard_mutex --> sb_writers#3 --> &p->lock Possible unsafe locking scenario: xt_socket: unknown flags 0x2 CPU0 CPU1 ---- ---- lock(&p->lock); lock(sb_writers#3); lock(&p->lock); lock(&sig->cred_guard_mutex); *** DEADLOCK *** 2 locks held by syz-executor.3/3534: #0: 00000000e60678f9 (&f->f_pos_lock){+.+.}, at: __fdget_pos+0x26f/0x310 fs/file.c:767 #1: 00000000e52eeead (&p->lock){+.+.}, at: seq_read+0x6b/0x11c0 fs/seq_file.c:164 stack backtrace: CPU: 1 PID: 3534 Comm: syz-executor.3 Not tainted 4.19.198-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x1fc/0x2ef lib/dump_stack.c:118 print_circular_bug.constprop.0.cold+0x2d7/0x41e kernel/locking/lockdep.c:1222 check_prev_add kernel/locking/lockdep.c:1866 [inline] check_prevs_add kernel/locking/lockdep.c:1979 [inline] validate_chain kernel/locking/lockdep.c:2420 [inline] __lock_acquire+0x30c9/0x3ff0 kernel/locking/lockdep.c:3416 lock_acquire+0x170/0x3c0 kernel/locking/lockdep.c:3908 __mutex_lock_common kernel/locking/mutex.c:938 [inline] __mutex_lock+0xd7/0x1200 kernel/locking/mutex.c:1083 do_io_accounting fs/proc/base.c:2750 [inline] proc_tid_io_accounting+0x184/0x2b0 fs/proc/base.c:2793 proc_single_show+0xeb/0x170 fs/proc/base.c:755 seq_read+0x4e0/0x11c0 fs/seq_file.c:232 __vfs_read+0xf7/0x750 fs/read_write.c:416 vfs_read+0x194/0x3c0 fs/read_write.c:452 ksys_read+0x12b/0x2a0 fs/read_write.c:579 do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x4665e9 Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 73 01 c3 48 c7 c1 bc ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f85e2507188 EFLAGS: 00000246 ORIG_RAX: 0000000000000000 RAX: ffffffffffffffda RBX: 000000000056bf80 RCX: 00000000004665e9 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000003 RBP: 00000000004bfcc4 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000056bf80 R13: 00007ffe6a6d1bff R14: 00007f85e2507300 R15: 0000000000022000 x_tables: ip6_tables: devgroup.0 match: invalid size 24 (kernel) != (user) 64 ubi: mtd0 is already attached to ubi0 ubi: mtd0 is already attached to ubi0 ubi0: detaching mtd0 ubi0: mtd0 is detached ubi0: attaching mtd0 ubi0: scanning is finished ubi0 error: ubi_attach_mtd_dev: cannot spawn "ubi_bgt0d", error -4 ubi0: attaching mtd0 ubi0: scanning is finished ubi0: attached mtd0 (name "mtdram test device", size 0 MiB) ubi0: PEB size: 4096 bytes (4 KiB), LEB size: 3968 bytes ubi0: min./max. I/O unit sizes: 1/64, sub-page size 1 ubi0: VID header offset: 64 (aligned 64), data offset: 128 ubi0: good PEBs: 32, bad PEBs: 0, corrupted PEBs: 0 ubi0: user volume: 0, internal volumes: 1, max. volumes count: 23 ubi0: max/mean erase counter: 1/1, WL threshold: 4096, image sequence number: 2069095535 ubi0: available PEBs: 28, total reserved PEBs: 4, PEBs reserved for bad PEB handling: 0 ubi0: background thread "ubi_bgt0d" started, PID 3874 ubi0: detaching mtd0 ubi0: mtd0 is detached ubi0: attaching mtd0 ubi0: scanning is finished tcpmss_tg4_check: 74 callbacks suppressed xt_TCPMSS: Only works on TCP SYN packets xt_TCPMSS: Only works on TCP SYN packets xt_TCPMSS: Only works on TCP SYN packets ubi0: attached mtd0 (name "mtdram test device", size 0 MiB) ubi0: PEB size: 4096 bytes (4 KiB), LEB size: 3968 bytes ubi0: min./max. I/O unit sizes: 1/64, sub-page size 1 ubi0: VID header offset: 64 (aligned 64), data offset: 128 ubi0: good PEBs: 32, bad PEBs: 0, corrupted PEBs: 0 ubi0: user volume: 0, internal volumes: 1, max. volumes count: 23 ubi0: max/mean erase counter: 1/1, WL threshold: 4096, image sequence number: 2069095535 ubi0: available PEBs: 28, total reserved PEBs: 4, PEBs reserved for bad PEB handling: 0 ubi0: background thread "ubi_bgt0d" started, PID 3950 ubi0: detaching mtd0 ubi0: mtd0 is detached xt_TCPMSS: Only works on TCP SYN packets ubi0: attaching mtd0 xt_TCPMSS: Only works on TCP SYN packets ubi0: scanning is finished xt_TCPMSS: Only works on TCP SYN packets xt_TCPMSS: Only works on TCP SYN packets xt_TCPMSS: Only works on TCP SYN packets ubi0: attached mtd0 (name "mtdram test device", size 0 MiB) ubi0: PEB size: 4096 bytes (4 KiB), LEB size: 3968 bytes ubi0: min./max. I/O unit sizes: 1/64, sub-page size 1 xt_TCPMSS: Only works on TCP SYN packets xt_TCPMSS: Only works on TCP SYN packets ubi0: VID header offset: 64 (aligned 64), data offset: 128 ubi0: good PEBs: 32, bad PEBs: 0, corrupted PEBs: 0 ubi0: user volume: 0, internal volumes: 1, max. volumes count: 23 ubi0: max/mean erase counter: 1/1, WL threshold: 4096, image sequence number: 2069095535 ubi0: available PEBs: 28, total reserved PEBs: 4, PEBs reserved for bad PEB handling: 0 ubi0: background thread "ubi_bgt0d" started, PID 4005 ubi0: detaching mtd0 ubi0: mtd0 is detached overlayfs: upperdir is in-use as upperdir/workdir of another mount, mount with '-o index=off' to override exclusive upperdir protection. socket_mt_v1_check: 23 callbacks suppressed xt_socket: unknown flags 0x2 xt_socket: unknown flags 0x2 xt_socket: unknown flags 0x2 xt_socket: unknown flags 0x2 xt_socket: unknown flags 0x2 xt_socket: unknown flags 0x2 xt_socket: unknown flags 0x2 overlayfs: upperdir is in-use as upperdir/workdir of another mount, mount with '-o index=off' to override exclusive upperdir protection. xt_socket: unknown flags 0x2 xt_socket: unknown flags 0x2 xt_socket: unknown flags 0x2 overlayfs: upperdir is in-use as upperdir/workdir of another mount, mount with '-o index=off' to override exclusive upperdir protection. tcpmss_tg4_check: 109 callbacks suppressed xt_TCPMSS: Only works on TCP SYN packets xt_TCPMSS: Only works on TCP SYN packets xt_TCPMSS: Only works on TCP SYN packets xt_TCPMSS: Only works on TCP SYN packets xt_TCPMSS: Only works on TCP SYN packets xt_TCPMSS: Only works on TCP SYN packets