bisecting fixing commit since a844dc4c544291470aa69edbe2434b040794e269 building syzkaller on d973f52833e0e3cec5406aa9cdf606a463d85c46 testing commit a844dc4c544291470aa69edbe2434b040794e269 with gcc (GCC) 8.1.0 kernel signature: d92ec036ff3ba2364e50c6d4730c84907f04fd5f all runs: crashed: inconsistent lock state in sp_get testing current HEAD b0cdffaa546e24acf92ab3b0d4e917a51aff6a82 testing commit b0cdffaa546e24acf92ab3b0d4e917a51aff6a82 with gcc (GCC) 8.1.0 kernel signature: 89563148acb4bcc906d4c466a624b00634edc0e3 all runs: OK # git bisect start b0cdffaa546e24acf92ab3b0d4e917a51aff6a82 a844dc4c544291470aa69edbe2434b040794e269 Bisecting: 318 revisions left to test after this (roughly 8 steps) [de7e8ca720e622aae4dde1b66fd8544741f15b9c] net: qlogic: Fix error paths in ql_alloc_large_buffers() testing commit de7e8ca720e622aae4dde1b66fd8544741f15b9c with gcc (GCC) 8.1.0 kernel signature: 1d2fe024129b4e70609dba5e0a74173631701567 all runs: crashed: inconsistent lock state in sp_get # git bisect good de7e8ca720e622aae4dde1b66fd8544741f15b9c Bisecting: 159 revisions left to test after this (roughly 7 steps) [c6ac111b46aa2b90e0f56af85fcb499d86f39177] scsi: lpfc: Fix locking on mailbox command completion testing commit c6ac111b46aa2b90e0f56af85fcb499d86f39177 with gcc (GCC) 8.1.0 kernel signature: ad9ea5e2044ae254ce3760b18a6e8b1de9492c2c all runs: crashed: inconsistent lock state in sp_get # git bisect good c6ac111b46aa2b90e0f56af85fcb499d86f39177 Bisecting: 79 revisions left to test after this (roughly 6 steps) [0ddfaacfb76d8d54a1f94bfa4e4bc9a7c452d4c7] gtp: do not allow adding duplicate tid and ms_addr pdp context testing commit 0ddfaacfb76d8d54a1f94bfa4e4bc9a7c452d4c7 with gcc (GCC) 8.1.0 kernel signature: 84245e7ee7978f3461d6132b4db23734b4f6f3d6 all runs: OK # git bisect bad 0ddfaacfb76d8d54a1f94bfa4e4bc9a7c452d4c7 Bisecting: 39 revisions left to test after this (roughly 5 steps) [a06d07dd52932800258d079a156eafd3d5dcc5b2] scripts/kallsyms: fix definitely-lost memory leak testing commit a06d07dd52932800258d079a156eafd3d5dcc5b2 with gcc (GCC) 8.1.0 kernel signature: d26b3e08a153848063759a6ba05a495a05914444 all runs: crashed: inconsistent lock state in sp_get # git bisect good a06d07dd52932800258d079a156eafd3d5dcc5b2 Bisecting: 19 revisions left to test after this (roughly 4 steps) [ff194a90990e8186e087387c0638ffc4d621cd57] netfilter: bridge: make sure to pull arp header in br_nf_forward_arp() testing commit ff194a90990e8186e087387c0638ffc4d621cd57 with gcc (GCC) 8.1.0 kernel signature: 54faee5a86635059ae042b7168897e62559fd35e all runs: OK # git bisect bad ff194a90990e8186e087387c0638ffc4d621cd57 Bisecting: 9 revisions left to test after this (roughly 3 steps) [b6829d2608ff945547eaaa22e76487db0c0b53f8] x86/mce: Fix possibly incorrect severity calculation on AMD testing commit b6829d2608ff945547eaaa22e76487db0c0b53f8 with gcc (GCC) 8.1.0 kernel signature: f276d3807cb2cccb9f1ffeb4c43fbc26ab06f91f all runs: crashed: inconsistent lock state in sp_get # git bisect good b6829d2608ff945547eaaa22e76487db0c0b53f8 Bisecting: 4 revisions left to test after this (roughly 2 steps) [29061e0875f853c3bed1d486ccf5ce476cc51afc] perf strbuf: Remove redundant va_end() in strbuf_addv() testing commit 29061e0875f853c3bed1d486ccf5ce476cc51afc with gcc (GCC) 8.1.0 kernel signature: 97da9287b872a1e63876342c1cdb615dd7d6f1f0 all runs: crashed: inconsistent lock state in sp_get # git bisect good 29061e0875f853c3bed1d486ccf5ce476cc51afc Bisecting: 2 revisions left to test after this (roughly 1 step) [9c0ffae88f7507078c7e6db73eda3b60478628eb] filldir[64]: remove WARN_ON_ONCE() for bad directory entries testing commit 9c0ffae88f7507078c7e6db73eda3b60478628eb with gcc (GCC) 8.1.0 kernel signature: cfd6b4aad29d7c1fd380028edd3e13145371b4f3 all runs: crashed: inconsistent lock state in sp_get # git bisect good 9c0ffae88f7507078c7e6db73eda3b60478628eb Bisecting: 0 revisions left to test after this (roughly 1 step) [8b58905f212b4880d94b5b8ae54e5b84e311947d] 6pack,mkiss: fix possible deadlock testing commit 8b58905f212b4880d94b5b8ae54e5b84e311947d with gcc (GCC) 8.1.0 kernel signature: dda321558e0d4578de7f382d956e956dac054bd8 all runs: OK # git bisect bad 8b58905f212b4880d94b5b8ae54e5b84e311947d Bisecting: 0 revisions left to test after this (roughly 0 steps) [69bb99133686bf9b8c7b5143c0bc2ae23d6cd63b] netfilter: ebtables: compat: reject all padding in matches/watchers testing commit 69bb99133686bf9b8c7b5143c0bc2ae23d6cd63b with gcc (GCC) 8.1.0 kernel signature: 38f044048dd293684e5fe76c339613102a7607ff all runs: crashed: inconsistent lock state in sp_get # git bisect good 69bb99133686bf9b8c7b5143c0bc2ae23d6cd63b 8b58905f212b4880d94b5b8ae54e5b84e311947d is the first bad commit commit 8b58905f212b4880d94b5b8ae54e5b84e311947d Author: Eric Dumazet Date: Thu Dec 12 10:32:13 2019 -0800 6pack,mkiss: fix possible deadlock commit 5c9934b6767b16ba60be22ec3cbd4379ad64170d upstream. We got another syzbot report [1] that tells us we must use write_lock_irq()/write_unlock_irq() to avoid possible deadlock. [1] WARNING: inconsistent lock state 5.5.0-rc1-syzkaller #0 Not tainted -------------------------------- inconsistent {HARDIRQ-ON-W} -> {IN-HARDIRQ-R} usage. syz-executor826/9605 [HC1[1]:SC0[0]:HE0:SE1] takes: ffffffff8a128718 (disc_data_lock){+-..}, at: sp_get.isra.0+0x1d/0xf0 drivers/net/ppp/ppp_synctty.c:138 {HARDIRQ-ON-W} state was registered at: lock_acquire+0x190/0x410 kernel/locking/lockdep.c:4485 __raw_write_lock_bh include/linux/rwlock_api_smp.h:203 [inline] _raw_write_lock_bh+0x33/0x50 kernel/locking/spinlock.c:319 sixpack_close+0x1d/0x250 drivers/net/hamradio/6pack.c:657 tty_ldisc_close.isra.0+0x119/0x1a0 drivers/tty/tty_ldisc.c:489 tty_set_ldisc+0x230/0x6b0 drivers/tty/tty_ldisc.c:585 tiocsetd drivers/tty/tty_io.c:2337 [inline] tty_ioctl+0xe8d/0x14f0 drivers/tty/tty_io.c:2597 vfs_ioctl fs/ioctl.c:47 [inline] file_ioctl fs/ioctl.c:545 [inline] do_vfs_ioctl+0x977/0x14e0 fs/ioctl.c:732 ksys_ioctl+0xab/0xd0 fs/ioctl.c:749 __do_sys_ioctl fs/ioctl.c:756 [inline] __se_sys_ioctl fs/ioctl.c:754 [inline] __x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:754 do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:294 entry_SYSCALL_64_after_hwframe+0x49/0xbe irq event stamp: 3946 hardirqs last enabled at (3945): [] __raw_spin_unlock_irq include/linux/spinlock_api_smp.h:168 [inline] hardirqs last enabled at (3945): [] _raw_spin_unlock_irq+0x23/0x80 kernel/locking/spinlock.c:199 hardirqs last disabled at (3946): [] trace_hardirqs_off_thunk+0x1a/0x1c arch/x86/entry/thunk_64.S:42 softirqs last enabled at (2658): [] spin_unlock_bh include/linux/spinlock.h:383 [inline] softirqs last enabled at (2658): [] clusterip_netdev_event+0x46f/0x670 net/ipv4/netfilter/ipt_CLUSTERIP.c:222 softirqs last disabled at (2656): [] spin_lock_bh include/linux/spinlock.h:343 [inline] softirqs last disabled at (2656): [] clusterip_netdev_event+0x1bb/0x670 net/ipv4/netfilter/ipt_CLUSTERIP.c:196 other info that might help us debug this: Possible unsafe locking scenario: CPU0 ---- lock(disc_data_lock); lock(disc_data_lock); *** DEADLOCK *** 5 locks held by syz-executor826/9605: #0: ffff8880a905e198 (&tty->legacy_mutex){+.+.}, at: tty_lock+0xc7/0x130 drivers/tty/tty_mutex.c:19 #1: ffffffff899a56c0 (rcu_read_lock){....}, at: mutex_spin_on_owner+0x0/0x330 kernel/locking/mutex.c:413 #2: ffff8880a496a2b0 (&(&i->lock)->rlock){-.-.}, at: spin_lock include/linux/spinlock.h:338 [inline] #2: ffff8880a496a2b0 (&(&i->lock)->rlock){-.-.}, at: serial8250_interrupt+0x2d/0x1a0 drivers/tty/serial/8250/8250_core.c:116 #3: ffffffff8c104048 (&port_lock_key){-.-.}, at: serial8250_handle_irq.part.0+0x24/0x330 drivers/tty/serial/8250/8250_port.c:1823 #4: ffff8880a905e090 (&tty->ldisc_sem){++++}, at: tty_ldisc_ref+0x22/0x90 drivers/tty/tty_ldisc.c:288 stack backtrace: CPU: 1 PID: 9605 Comm: syz-executor826 Not tainted 5.5.0-rc1-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+0x197/0x210 lib/dump_stack.c:118 print_usage_bug.cold+0x327/0x378 kernel/locking/lockdep.c:3101 valid_state kernel/locking/lockdep.c:3112 [inline] mark_lock_irq kernel/locking/lockdep.c:3309 [inline] mark_lock+0xbb4/0x1220 kernel/locking/lockdep.c:3666 mark_usage kernel/locking/lockdep.c:3554 [inline] __lock_acquire+0x1e55/0x4a00 kernel/locking/lockdep.c:3909 lock_acquire+0x190/0x410 kernel/locking/lockdep.c:4485 __raw_read_lock include/linux/rwlock_api_smp.h:149 [inline] _raw_read_lock+0x32/0x50 kernel/locking/spinlock.c:223 sp_get.isra.0+0x1d/0xf0 drivers/net/ppp/ppp_synctty.c:138 sixpack_write_wakeup+0x25/0x340 drivers/net/hamradio/6pack.c:402 tty_wakeup+0xe9/0x120 drivers/tty/tty_io.c:536 tty_port_default_wakeup+0x2b/0x40 drivers/tty/tty_port.c:50 tty_port_tty_wakeup+0x57/0x70 drivers/tty/tty_port.c:387 uart_write_wakeup+0x46/0x70 drivers/tty/serial/serial_core.c:104 serial8250_tx_chars+0x495/0xaf0 drivers/tty/serial/8250/8250_port.c:1761 serial8250_handle_irq.part.0+0x2a2/0x330 drivers/tty/serial/8250/8250_port.c:1834 serial8250_handle_irq drivers/tty/serial/8250/8250_port.c:1820 [inline] serial8250_default_handle_irq+0xc0/0x150 drivers/tty/serial/8250/8250_port.c:1850 serial8250_interrupt+0xf1/0x1a0 drivers/tty/serial/8250/8250_core.c:126 __handle_irq_event_percpu+0x15d/0x970 kernel/irq/handle.c:149 handle_irq_event_percpu+0x74/0x160 kernel/irq/handle.c:189 handle_irq_event+0xa7/0x134 kernel/irq/handle.c:206 handle_edge_irq+0x25e/0x8d0 kernel/irq/chip.c:830 generic_handle_irq_desc include/linux/irqdesc.h:156 [inline] do_IRQ+0xde/0x280 arch/x86/kernel/irq.c:250 common_interrupt+0xf/0xf arch/x86/entry/entry_64.S:607 RIP: 0010:cpu_relax arch/x86/include/asm/processor.h:685 [inline] RIP: 0010:mutex_spin_on_owner+0x247/0x330 kernel/locking/mutex.c:579 Code: c3 be 08 00 00 00 4c 89 e7 e8 e5 06 59 00 4c 89 e0 48 c1 e8 03 42 80 3c 38 00 0f 85 e1 00 00 00 49 8b 04 24 a8 01 75 96 f3 90 2f fe ff ff 0f 0b e8 0d 19 09 00 84 c0 0f 85 ff fd ff ff 48 c7 RSP: 0018:ffffc90001eafa20 EFLAGS: 00000246 ORIG_RAX: ffffffffffffffd7 RAX: 0000000000000000 RBX: ffff88809fd9e0c0 RCX: 1ffffffff13266dd RDX: 0000000000000000 RSI: 0000000000000008 RDI: 0000000000000000 RBP: ffffc90001eafa60 R08: 1ffff11013d22898 R09: ffffed1013d22899 R10: ffffed1013d22898 R11: ffff88809e9144c7 R12: ffff8880a905e138 R13: ffff88809e9144c0 R14: 0000000000000000 R15: dffffc0000000000 mutex_optimistic_spin kernel/locking/mutex.c:673 [inline] __mutex_lock_common kernel/locking/mutex.c:962 [inline] __mutex_lock+0x32b/0x13c0 kernel/locking/mutex.c:1106 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:1121 tty_lock+0xc7/0x130 drivers/tty/tty_mutex.c:19 tty_release+0xb5/0xe90 drivers/tty/tty_io.c:1665 __fput+0x2ff/0x890 fs/file_table.c:280 ____fput+0x16/0x20 fs/file_table.c:313 task_work_run+0x145/0x1c0 kernel/task_work.c:113 exit_task_work include/linux/task_work.h:22 [inline] do_exit+0x8e7/0x2ef0 kernel/exit.c:797 do_group_exit+0x135/0x360 kernel/exit.c:895 __do_sys_exit_group kernel/exit.c:906 [inline] __se_sys_exit_group kernel/exit.c:904 [inline] __x64_sys_exit_group+0x44/0x50 kernel/exit.c:904 do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:294 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x43fef8 Code: Bad RIP value. RSP: 002b:00007ffdb07d2338 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 000000000043fef8 RDX: 0000000000000000 RSI: 000000000000003c RDI: 0000000000000000 RBP: 00000000004bf730 R08: 00000000000000e7 R09: ffffffffffffffd0 R10: 00000000004002c8 R11: 0000000000000246 R12: 0000000000000001 R13: 00000000006d1180 R14: 0000000000000000 R15: 0000000000000000 Fixes: 6e4e2f811bad ("6pack,mkiss: fix lock inconsistency") Signed-off-by: Eric Dumazet Reported-by: syzbot Cc: Arnd Bergmann Signed-off-by: Jakub Kicinski Signed-off-by: Greg Kroah-Hartman drivers/net/hamradio/6pack.c | 4 ++-- drivers/net/hamradio/mkiss.c | 4 ++-- 2 files changed, 4 insertions(+), 4 deletions(-) culprit signature: dda321558e0d4578de7f382d956e956dac054bd8 parent signature: 38f044048dd293684e5fe76c339613102a7607ff revisions tested: 12, total time: 2h55m48.422260919s (build: 1h39m14.287754795s, test: 1h15m11.36050152s) first good commit: 8b58905f212b4880d94b5b8ae54e5b84e311947d 6pack,mkiss: fix possible deadlock cc: ["edumazet@google.com" "gregkh@linuxfoundation.org" "jakub.kicinski@netronome.com"]