bisecting fixing commit since f4bc5bbb5fef3cf421ba3485d6d383c27ec473ed building syzkaller on 0b33604d8e2793b82ec89abecf82d92b82e3d410 testing commit f4bc5bbb5fef3cf421ba3485d6d383c27ec473ed compiler: gcc (GCC) 10.2.1 20210217, GNU ld (GNU Binutils for Debian) 2.35.2 kernel signature: f45e03bb8fd4a8a79a818fa7f33fc18b7b4245ea1167eda3ceb7bea373b3382f run #0: crashed: general protection fault in l2cap_chan_timeout run #1: crashed: general protection fault in l2cap_chan_timeout run #2: crashed: general protection fault in l2cap_chan_timeout run #3: crashed: general protection fault in l2cap_chan_timeout run #4: crashed: general protection fault in l2cap_chan_timeout run #5: crashed: general protection fault in l2cap_chan_timeout run #6: crashed: general protection fault in l2cap_chan_timeout run #7: crashed: general protection fault in l2cap_chan_timeout run #8: crashed: general protection fault in l2cap_chan_timeout run #9: crashed: general protection fault in l2cap_chan_timeout run #10: crashed: general protection fault in l2cap_chan_timeout run #11: OK run #12: OK run #13: crashed: general protection fault in l2cap_chan_timeout run #14: OK run #15: OK run #16: OK run #17: OK run #18: OK run #19: OK testing current HEAD ce522ba9ef7e2d9fb22a39eb3371c0c64e2a433e testing commit ce522ba9ef7e2d9fb22a39eb3371c0c64e2a433e compiler: gcc (GCC) 10.2.1 20210217, GNU ld (GNU Binutils for Debian) 2.35.2 kernel signature: 802052105ab27e3bee6dc9afaa8ae657298d3139a6c36d47e12eb6315b7216b3 run #0: crashed: general protection fault in l2cap_chan_timeout run #1: crashed: general protection fault in l2cap_chan_timeout run #2: crashed: general protection fault in l2cap_chan_timeout run #3: crashed: general protection fault in l2cap_chan_timeout run #4: crashed: general protection fault in l2cap_chan_timeout run #5: crashed: general protection fault in l2cap_chan_timeout run #6: OK run #7: OK run #8: OK run #9: OK revisions tested: 2, total time: 22m32.296653232s (build: 11m40.854132814s, test: 10m21.11679177s) the crash still happens on HEAD commit msg: Linux 5.18-rc2 crash: general protection fault in l2cap_chan_timeout general protection fault, probably for non-canonical address 0xdffffc000000005a: 0000 [#1] PREEMPT SMP KASAN KASAN: null-ptr-deref in range [0x00000000000002d0-0x00000000000002d7] CPU: 1 PID: 2925 Comm: kworker/1:3 Not tainted 5.18.0-rc2-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: events l2cap_chan_timeout RIP: 0010:__mutex_lock_common kernel/locking/mutex.c:579 [inline] RIP: 0010:__mutex_lock+0xec/0x12f0 kernel/locking/mutex.c:733 Code: d0 7c 08 84 d2 0f 85 65 0f 00 00 8b 15 5d 17 b0 06 85 d2 75 29 48 8d 7d 60 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 <80> 3c 02 00 0f 85 5e 0f 00 00 48 3b 6d 60 0f 85 90 08 00 00 bf 01 RSP: 0018:ffffc9000b17fb98 EFLAGS: 00010206 RAX: dffffc0000000000 RBX: 0000000000000000 RCX: 0000000000000001 RDX: 000000000000005a RSI: ffffffff88eb8d00 RDI: 00000000000002d0 RBP: 0000000000000270 R08: ffffffff878a4a2c R09: ffffffff8ca2cbd7 R10: fffffbfff194597a R11: 0000000000000001 R12: 0000000000000000 R13: dffffc0000000000 R14: ffff88807cfd4020 R15: 0000000000000001 FS: 0000000000000000(0000) GS:ffff8880b9f00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000020000140 CR3: 0000000023de6000 CR4: 00000000003506e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: l2cap_chan_timeout+0x5c/0x280 net/bluetooth/l2cap_core.c:422 process_one_work+0x841/0x13a0 kernel/workqueue.c:2289 worker_thread+0x598/0xec0 kernel/workqueue.c:2436 kthread+0x299/0x340 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:298 Modules linked in: ---[ end trace 0000000000000000 ]--- RIP: 0010:__mutex_lock_common kernel/locking/mutex.c:579 [inline] RIP: 0010:__mutex_lock+0xec/0x12f0 kernel/locking/mutex.c:733 Code: d0 7c 08 84 d2 0f 85 65 0f 00 00 8b 15 5d 17 b0 06 85 d2 75 29 48 8d 7d 60 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 <80> 3c 02 00 0f 85 5e 0f 00 00 48 3b 6d 60 0f 85 90 08 00 00 bf 01 RSP: 0018:ffffc9000b17fb98 EFLAGS: 00010206 RAX: dffffc0000000000 RBX: 0000000000000000 RCX: 0000000000000001 RDX: 000000000000005a RSI: ffffffff88eb8d00 RDI: 00000000000002d0 RBP: 0000000000000270 R08: ffffffff878a4a2c R09: ffffffff8ca2cbd7 R10: fffffbfff194597a R11: 0000000000000001 R12: 0000000000000000 R13: dffffc0000000000 R14: ffff88807cfd4020 R15: 0000000000000001 FS: 0000000000000000(0000) GS:ffff8880b9f00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000020000140 CR3: 00000000193c5000 CR4: 00000000003506e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 ---------------- Code disassembly (best guess): 0: d0 7c 08 84 sarb -0x7c(%rax,%rcx,1) 4: d2 0f rorb %cl,(%rdi) 6: 85 65 0f test %esp,0xf(%rbp) 9: 00 00 add %al,(%rax) b: 8b 15 5d 17 b0 06 mov 0x6b0175d(%rip),%edx # 0x6b0176e 11: 85 d2 test %edx,%edx 13: 75 29 jne 0x3e 15: 48 8d 7d 60 lea 0x60(%rbp),%rdi 19: 48 b8 00 00 00 00 00 movabs $0xdffffc0000000000,%rax 20: fc ff df 23: 48 89 fa mov %rdi,%rdx 26: 48 c1 ea 03 shr $0x3,%rdx * 2a: 80 3c 02 00 cmpb $0x0,(%rdx,%rax,1) <-- trapping instruction 2e: 0f 85 5e 0f 00 00 jne 0xf92 34: 48 3b 6d 60 cmp 0x60(%rbp),%rbp 38: 0f 85 90 08 00 00 jne 0x8ce 3e: bf .byte 0xbf 3f: 01 .byte 0x1