bisecting fixing commit since abb3438d69fb6dd5baa4ae23eafbf5b87945eff1 building syzkaller on 344da168cb738076d82a75e1a7a1f5177df8dbc7 testing commit abb3438d69fb6dd5baa4ae23eafbf5b87945eff1 with gcc (GCC) 8.1.0 kernel signature: 32c331f5505b8f94642c2224e2b470b37f87b2902f1a6712a31519d064e5b7b0 run #0: crashed: general protection fault in afs_proc_cell_setup run #1: crashed: BUG: unable to handle kernel NULL pointer dereference in afs_deactivate_cell run #2: crashed: WARNING: ODEBUG bug in __do_softirq run #3: crashed: WARNING in __proc_create run #4: crashed: BUG: unable to handle kernel paging request in afs_proc_cell_remove run #5: crashed: WARNING: ODEBUG bug in __do_softirq run #6: crashed: WARNING: proc registration bug in afs_manage_cell run #7: crashed: general protection fault in afs_proc_cell_remove run #8: crashed: general protection fault in afs_deactivate_cell run #9: crashed: BUG: unable to handle kernel NULL pointer dereference in afs_deactivate_cell testing current HEAD c85fb28b6f999db9928b841f63f1beeb3074eeca testing commit c85fb28b6f999db9928b841f63f1beeb3074eeca with gcc (GCC) 8.1.0 kernel signature: ed544403da210be58c7e7231c58cb60f3c0085e1aee67dc5920fb4b15882347a run #0: crashed: BUG: unable to handle kernel paging request in afs_proc_cell_setup run #1: crashed: WARNING in __xlate_proc_name run #2: crashed: general protection fault in afs_deactivate_cell run #3: crashed: BUG: unable to handle kernel NULL pointer dereference in afs_manage_cell run #4: crashed: BUG: unable to handle kernel paging request in afs_proc_cell_remove run #5: crashed: BUG: unable to handle kernel paging request in afs_proc_cell_remove run #6: OK run #7: crashed: WARNING: ODEBUG bug in __do_softirq run #8: crashed: BUG: unable to handle kernel NULL pointer dereference in afs_deactivate_cell run #9: crashed: INFO: rcu detected stall in sys_mount revisions tested: 2, total time: 22m51.077039304s (build: 9m56.841603396s, test: 12m24.624881671s) the crash still happens on HEAD commit msg: Merge tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux crash: INFO: rcu detected stall in sys_mount rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): ------------[ cut here ]------------ WARNING: CPU: 1 PID: 19452 at kernel/sched/core.c:3013 try_invoke_on_locked_down_task+0x97/0x100 kernel/sched/core.c:3033 Kernel panic - not syncing: panic_on_warn set ... CPU: 1 PID: 19452 Comm: syz-executor.0 Not tainted 5.9.0-rc8-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+0xa3/0xcc lib/dump_stack.c:118 panic+0x135/0x31a kernel/panic.c:231 __warn.cold.13+0x20/0x25 kernel/panic.c:600 report_bug+0xc0/0xf0 lib/bug.c:198 handle_bug+0x35/0x90 arch/x86/kernel/traps.c:234 exc_invalid_op+0x13/0x60 arch/x86/kernel/traps.c:254 asm_exc_invalid_op+0x12/0x20 arch/x86/include/asm/idtentry.h:536 RIP: 0010:try_invoke_on_locked_down_task+0x97/0x100 kernel/sched/core.c:3013 Code: 48 89 ef e8 fb 39 e5 01 44 89 e0 48 8b 4c 24 10 65 48 33 0c 25 28 00 00 00 75 6e 48 83 c4 18 5b 5d 41 5c 41 5d 41 5e 41 5f c3 <0f> 0b eb a1 48 89 e6 48 89 df 45 31 e4 e8 c7 c2 ff ff 8b 53 40 49 RSP: 0018:ffffc90000d08e00 EFLAGS: 00010046 RAX: 0000000000000000 RBX: ffff88810d560340 RCX: 0000000000000001 RDX: ffffc90000d08e84 RSI: ffffffff8125c500 RDI: ffff88810d560340 RBP: ffff88810d560340 R08: ffffffff85d2e422 R09: 0000000000000033 R10: ffff88810d5606c0 R11: 0000000000000001 R12: 000000000002e9c0 R13: ffffffff8125c500 R14: ffffc90000d08e84 R15: 0000000000003989 rcu_print_task_stall kernel/rcu/tree_stall.h:267 [inline] print_other_cpu_stall kernel/rcu/tree_stall.h:475 [inline] check_cpu_stall kernel/rcu/tree_stall.h:634 [inline] rcu_pending kernel/rcu/tree.c:3639 [inline] rcu_sched_clock_irq.cold.94+0x243/0x52d kernel/rcu/tree.c:2521 update_process_times+0x1f/0x60 kernel/time/timer.c:1710 tick_sched_handle.isra.24+0x1a/0x50 kernel/time/tick-sched.c:176 tick_sched_timer+0x6c/0x80 kernel/time/tick-sched.c:1328 __run_hrtimer kernel/time/hrtimer.c:1524 [inline] __hrtimer_run_queues+0x1e1/0x510 kernel/time/hrtimer.c:1588 hrtimer_interrupt+0xf9/0x210 kernel/time/hrtimer.c:1650 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1080 [inline] __sysvec_apic_timer_interrupt+0x8e/0x2b0 arch/x86/kernel/apic/apic.c:1097 asm_call_irq_on_stack+0xf/0x20 __run_sysvec_on_irqstack arch/x86/include/asm/irq_stack.h:37 [inline] run_sysvec_on_irqstack_cond arch/x86/include/asm/irq_stack.h:89 [inline] sysvec_apic_timer_interrupt+0xc1/0xe0 arch/x86/kernel/apic/apic.c:1091 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:581 RIP: 0010:strncasecmp+0x24/0x90 lib/string.c:52 Code: 84 00 00 00 00 00 31 c0 48 85 d2 74 65 55 45 31 c9 53 eb 16 83 c1 20 45 84 d2 75 50 41 38 cb 75 65 49 83 c1 01 4c 39 ca 74 52 <42> 0f b6 0c 0f 46 0f b6 04 0e 84 c9 45 89 c3 74 38 45 84 c0 74 33 RSP: 0018:ffffc9000a28bc80 EFLAGS: 00000206 RAX: 0000000000000000 RBX: ffff88810da01400 RCX: 00000000000000ee RDX: 0000000000000005 RSI: ffff88810d264921 RDI: ffff88810d228f40 RBP: 0000000000000005 R08: 00000000000000ee R09: 0000000000000002 R10: 0000000000000001 R11: 00000000000000ee R12: ffff88810d264921 R13: ffff88810d228f40 R14: ffff888119d92000 R15: 0000000000000005 afs_lookup_cell_rcu+0x204/0x390 fs/afs/cell.c:88 afs_lookup_cell+0x84/0x700 fs/afs/cell.c:249 afs_parse_source fs/afs/super.c:290 [inline] afs_parse_param+0x12d/0x230 fs/afs/super.c:326 vfs_parse_fs_param+0x90/0x190 fs/fs_context.c:117 vfs_parse_fs_string+0x70/0xa0 fs/fs_context.c:161 generic_parse_monolithic+0x8f/0xc0 fs/fs_context.c:201 do_new_mount fs/namespace.c:2871 [inline] path_mount+0x6c0/0xa60 fs/namespace.c:3192 do_mount+0x70/0x90 fs/namespace.c:3205 __do_sys_mount fs/namespace.c:3413 [inline] __se_sys_mount fs/namespace.c:3390 [inline] __x64_sys_mount+0xbf/0xe0 fs/namespace.c:3390 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x45ffca Code: b8 a6 00 00 00 0f 05 48 3d 01 f0 ff ff 0f 83 fd 89 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 49 89 ca b8 a5 00 00 00 0f 05 <48> 3d 01 f0 ff ff 0f 83 da 89 fb ff c3 66 0f 1f 84 00 00 00 00 00 RSP: 002b:00007fd7b0fdaa88 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5 RAX: ffffffffffffffda RBX: 00007fd7b0fdab20 RCX: 000000000045ffca RDX: 0000000020000040 RSI: 0000000020002480 RDI: 0000000000000000 RBP: 00007fd7b0fdaae0 R08: 00007fd7b0fdab20 R09: 0000000020000040 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000020000040 R13: 0000000020002480 R14: 0000000000000000 R15: 0000000020000180 Kernel Offset: disabled Rebooting in 86400 seconds..