Hello, syzbot found the following crash on: HEAD commit: 468c2a10 mlxsw: spectrum_trap: fix unintention integer ove.. git tree: net console output: https://syzkaller.appspot.com/x/log.txt?x=11089cb3e00000 kernel config: https://syzkaller.appspot.com/x/.config?x=8c1e98458335a7d1 dashboard link: https://syzkaller.appspot.com/bug?extid=fc0674cde00b66844470 compiler: gcc (GCC) 9.0.0 20181231 (experimental) syz repro: https://syzkaller.appspot.com/x/repro.syz?x=115f2a43e00000 C reproducer: https://syzkaller.appspot.com/x/repro.c?x=141ea0ede00000 The bug was bisected to: commit 4f87ee118d16b4b2116a477229573ed5003b0d78 Author: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx> Date: Sat Dec 7 14:15:17 2019 +0000 crypto: api - Do not zap spawn->alg bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=10ffbc2be00000 final crash: https://syzkaller.appspot.com/x/report.txt?x=12ffbc2be00000 console output: https://syzkaller.appspot.com/x/log.txt?x=14ffbc2be00000 IMPORTANT: if you fix the bug, please add the following tag to the commit: Reported-by: syzbot+fc0674cde00b66844470@xxxxxxxxxxxxxxxxxxxxxxxxx Fixes: 4f87ee118d16 ("crypto: api - Do not zap spawn->alg") ------------[ cut here ]------------ refcount_t: underflow; use-after-free. WARNING: CPU: 0 PID: 7174 at lib/refcount.c:28 refcount_warn_saturate+0x1d1/0x1e0 lib/refcount.c:28 Kernel panic - not syncing: panic_on_warn set ... CPU: 0 PID: 7174 Comm: syz-executor413 Not tainted 5.6.0-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+0x188/0x20d lib/dump_stack.c:118 panic+0x2e3/0x75c kernel/panic.c:221 __warn.cold+0x2f/0x35 kernel/panic.c:582 report_bug+0x27b/0x2f0 lib/bug.c:195 fixup_bug arch/x86/kernel/traps.c:175 [inline] fixup_bug arch/x86/kernel/traps.c:170 [inline] do_error_trap+0x12b/0x220 arch/x86/kernel/traps.c:267 do_invalid_op+0x32/0x40 arch/x86/kernel/traps.c:286 invalid_op+0x23/0x30 arch/x86/entry/entry_64.S:1027 RIP: 0010:refcount_warn_saturate+0x1d1/0x1e0 lib/refcount.c:28 Code: e9 db fe ff ff 48 89 df e8 2c 95 1e fe e9 8a fe ff ff e8 c2 81 e1 fd 48 c7 c7 40 c6 71 88 c6 05 82 bd f1 06 01 e8 17 f6 b2 fd <0f> 0b e9 af fe ff ff 0f 1f 84 00 00 00 00 00 41 56 41 55 41 54 55 RSP: 0018:ffffc90001a17b18 EFLAGS: 00010282 RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000 RDX: 0000000000000000 RSI: ffffffff815ca861 RDI: fffff52000342f55 RBP: 0000000000000003 R08: ffff8880949fe300 R09: ffffed1015cc66a1 R10: ffffed1015cc66a0 R11: ffff8880ae633507 R12: ffff88809a6d187c R13: ffff8880a40eb000 R14: 0000000000000000 R15: ffff8880a40eb010 refcount_sub_and_test include/linux/refcount.h:261 [inline] refcount_dec_and_test include/linux/refcount.h:281 [inline] crypto_alg_put crypto/internal.h:93 [inline] crypto_mod_put crypto/api.c:45 [inline] crypto_destroy_tfm+0x2a1/0x310 crypto/api.c:566 crypto_exit_ops crypto/api.c:308 [inline] crypto_destroy_tfm+0xb1/0x310 crypto/api.c:565 crypto_free_aead include/crypto/aead.h:185 [inline] aead_release+0x2d/0x50 crypto/algif_aead.c:506 alg_do_release crypto/af_alg.c:114 [inline] alg_sock_destruct+0x85/0xe0 crypto/af_alg.c:358 __sk_destruct+0x4b/0x7c0 net/core/sock.c:1696 sk_destruct+0xc6/0x100 net/core/sock.c:1740 __sk_free+0xef/0x3d0 net/core/sock.c:1751 sk_free+0x78/0xa0 net/core/sock.c:1762 sock_put include/net/sock.h:1778 [inline] af_alg_release+0xdb/0x110 crypto/af_alg.c:121 __sock_release+0xcd/0x280 net/socket.c:605 sock_close+0x18/0x20 net/socket.c:1283 __fput+0x2e9/0x860 fs/file_table.c:280 task_work_run+0xf4/0x1b0 kernel/task_work.c:123 exit_task_work include/linux/task_work.h:22 [inline] do_exit+0xb34/0x2dd0 kernel/exit.c:793 do_group_exit+0x125/0x340 kernel/exit.c:891 __do_sys_exit_group kernel/exit.c:902 [inline] __se_sys_exit_group kernel/exit.c:900 [inline] __x64_sys_exit_group+0x3a/0x50 kernel/exit.c:900 do_syscall_64+0xf6/0x7d0 arch/x86/entry/common.c:295 entry_SYSCALL_64_after_hwframe+0x49/0xb3 RIP: 0033:0x43ff78 Code: 00 00 be 3c 00 00 00 eb 19 66 0f 1f 84 00 00 00 00 00 48 89 d7 89 f0 0f 05 48 3d 00 f0 ff ff 77 21 f4 48 89 d7 44 89 c0 0f 05 <48> 3d 00 f0 ff ff 76 e0 f7 d8 64 41 89 01 eb d8 0f 1f 84 00 00 00 RSP: 002b:00007ffe423e1db8 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 000000000043ff78 RDX: 0000000000000000 RSI: 000000000000003c RDI: 0000000000000000 RBP: 00000000004bf850 R08: 00000000000000e7 R09: ffffffffffffffd0 R10: 00000000004002c8 R11: 0000000000000246 R12: 0000000000000001 R13: 00000000006d1180 R14: 0000000000000000 R15: 0000000000000000 Kernel Offset: disabled Rebooting in 86400 seconds.. --- This bug is generated by a bot. It may contain errors. See https://goo.gl/tpsmEJ for more information about syzbot. syzbot engineers can be reached at syzkaller@xxxxxxxxxxxxxxxx. syzbot will keep track of this bug report. See: https://goo.gl/tpsmEJ#status for how to communicate with syzbot. For information about bisection process see: https://goo.gl/tpsmEJ#bisection syzbot can test patches for this bug, for details see: https://goo.gl/tpsmEJ#testing-patches
