bisecting fixing commit since 0c88e405c97ed1828443b67891e6d4bb6e56cd4e building syzkaller on a0092f9dfdd33924abe5cf5565e4ec4748217c7b testing commit 0c88e405c97ed1828443b67891e6d4bb6e56cd4e with gcc (GCC) 8.4.1 20210217 kernel signature: 11555df5446753c27b333aad3532c23e89b171a4588ce982491a3e74eec70fe9 run #0: crashed: BUG: unable to handle kernel NULL pointer dereference in rhashtable_free_and_destroy run #1: crashed: INFO: trying to register non-static key in rhashtable_free_and_destroy run #2: crashed: BUG: unable to handle kernel NULL pointer dereference in rhashtable_free_and_destroy run #3: crashed: BUG: unable to handle kernel NULL pointer dereference in rhashtable_free_and_destroy run #4: crashed: INFO: trying to register non-static key in rhashtable_free_and_destroy run #5: crashed: KASAN: wild-memory-access Write in rhashtable_free_and_destroy run #6: crashed: INFO: trying to register non-static key in rhashtable_free_and_destroy run #7: crashed: KASAN: wild-memory-access Write in rhashtable_free_and_destroy run #8: crashed: INFO: trying to register non-static key in rhashtable_free_and_destroy run #9: crashed: KASAN: wild-memory-access Write in rhashtable_free_and_destroy run #10: crashed: INFO: trying to register non-static key in rhashtable_free_and_destroy run #11: crashed: BUG: unable to handle kernel NULL pointer dereference in rhashtable_free_and_destroy run #12: crashed: BUG: unable to handle kernel NULL pointer dereference in rhashtable_free_and_destroy run #13: crashed: general protection fault in get_work_pool_id run #14: crashed: KASAN: wild-memory-access Write in rhashtable_free_and_destroy run #15: crashed: BUG: unable to handle kernel NULL pointer dereference in rhashtable_free_and_destroy run #16: crashed: BUG: unable to handle kernel NULL pointer dereference in rhashtable_free_and_destroy run #17: crashed: INFO: trying to register non-static key in rhashtable_free_and_destroy run #18: crashed: INFO: trying to register non-static key in rhashtable_free_and_destroy run #19: crashed: INFO: task hung in rtnl_lock testing current HEAD 6b7b0056defc6eb5c87bbe4690ccda547b2891aa testing commit 6b7b0056defc6eb5c87bbe4690ccda547b2891aa with gcc (GCC) 8.4.1 20210217 kernel signature: 0c5cef414711e9c15d0589597626fe8965f43990fd1de169495d92eed9cf527c all runs: crashed: BUG: unable to handle kernel NULL pointer dereference in rhashtable_free_and_destroy revisions tested: 2, total time: 31m6.920536084s (build: 20m56.849794583s, test: 9m27.920074474s) the crash still happens on HEAD commit msg: Linux 4.19.192 crash: BUG: unable to handle kernel NULL pointer dereference in rhashtable_free_and_destroy RDX: 0000000000000000 RSI: 00000000200006c0 RDI: 0000000000000003 RBP: 00007fe8bad481d0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000002 R13: 00007ffc41d56a1f R14: 00007fe8bad48300 R15: 0000000000022000 BUG: unable to handle kernel NULL pointer dereference at 0000000000000080 PGD 0 P4D 0 Oops: 0002 [#1] PREEMPT SMP KASAN CPU: 1 PID: 9673 Comm: kworker/1:4 Not tainted 4.19.192-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: events cfg80211_destroy_iface_wk RIP: 0010:test_and_set_bit arch/x86/include/asm/bitops.h:209 [inline] RIP: 0010:try_to_grab_pending+0xb8/0x5f0 kernel/workqueue.c:1228 Code: 00 00 00 00 fc ff df 4c 89 e2 48 c1 ea 03 80 3c 02 00 0f 85 0f 04 00 00 4d 89 34 24 e8 81 76 26 00 45 84 ed 0f 85 54 01 00 00 48 0f ba 2b 00 72 11 31 c0 48 83 c4 10 5b 41 5c 41 5d 41 5e 41 RSP: 0018:ffff8880b31677f8 EFLAGS: 00010046 RAX: 0000000000000007 RBX: 0000000000000080 RCX: 0000000000000000 RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff88809fa0cccc RBP: ffff8880b3167830 R08: ffff88809fa0cd78 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: ffff8880b3167868 R13: 0000000000000000 R14: 0000000000000282 R15: 0000000000000080 FS: 0000000000000000(0000) GS:ffff8880ba300000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000080 CR3: 000000000986d000 CR4: 00000000001406e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: __cancel_work_timer+0x9b/0x430 kernel/workqueue.c:2971 cancel_work_sync+0xb/0x10 kernel/workqueue.c:3048 rhashtable_free_and_destroy+0x25/0x690 lib/rhashtable.c:1145 mesh_table_free net/mac80211/mesh_pathtbl.c:73 [inline] mesh_pathtbl_unregister+0x43/0xa0 net/mac80211/mesh_pathtbl.c:825 ieee80211_mesh_teardown_sdata+0x15/0x20 net/mac80211/mesh.c:1478 ieee80211_teardown_sdata+0x1c4/0x270 net/mac80211/iface.c:1126 ieee80211_uninit+0x10/0x20 net/mac80211/iface.c:1131 rollback_registered_many+0x849/0xbe0 net/core/dev.c:8202 rollback_registered+0xdc/0x190 net/core/dev.c:8230 unregister_netdevice_queue+0x186/0x240 net/core/dev.c:9297 unregister_netdevice include/linux/netdevice.h:2615 [inline] ieee80211_if_remove+0x1db/0x2d0 net/mac80211/iface.c:1925 ieee80211_del_iface+0xd/0x20 net/mac80211/cfg.c:144 rdev_del_virtual_intf net/wireless/rdev-ops.h:57 [inline] cfg80211_destroy_ifaces+0xe3/0x540 net/wireless/core.c:317 cfg80211_destroy_iface_wk+0x19/0x30 net/wireless/core.c:329 process_one_work+0x7b9/0x15a0 kernel/workqueue.c:2152 worker_thread+0x85/0xb60 kernel/workqueue.c:2295 kthread+0x347/0x410 kernel/kthread.c:259 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:415 Modules linked in: CR2: 0000000000000080 ---[ end trace aa0f456d98eed352 ]--- RIP: 0010:test_and_set_bit arch/x86/include/asm/bitops.h:209 [inline] RIP: 0010:try_to_grab_pending+0xb8/0x5f0 kernel/workqueue.c:1228 Code: 00 00 00 00 fc ff df 4c 89 e2 48 c1 ea 03 80 3c 02 00 0f 85 0f 04 00 00 4d 89 34 24 e8 81 76 26 00 45 84 ed 0f 85 54 01 00 00 48 0f ba 2b 00 72 11 31 c0 48 83 c4 10 5b 41 5c 41 5d 41 5e 41 RSP: 0018:ffff8880b31677f8 EFLAGS: 00010046 RAX: 0000000000000007 RBX: 0000000000000080 RCX: 0000000000000000 RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff88809fa0cccc RBP: ffff8880b3167830 R08: ffff88809fa0cd78 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: ffff8880b3167868 R13: 0000000000000000 R14: 0000000000000282 R15: 0000000000000080 FS: 0000000000000000(0000) GS:ffff8880ba300000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000080 CR3: 000000000986d000 CR4: 00000000001406e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400