bisecting fixing commit since e6a95d8851f1e993269b2172595107061f9371ae building syzkaller on 0159583c3bcfe4ece6b839712327cd955aabee66 testing commit e6a95d8851f1e993269b2172595107061f9371ae with gcc (GCC) 8.1.0 kernel signature: 77c831f43f7aa9d533b5a002b4b4d05d781d14a2b4e8cfd400448a4ae55d61e2 run #0: crashed: KASAN: use-after-free Write in padata_parallel_worker run #1: crashed: KASAN: use-after-free in padata_parallel_worker run #2: crashed: BUG: unable to handle kernel run #3: crashed: KASAN: use-after-free Write in padata_parallel_worker run #4: crashed: BUG: unable to handle kernel NULL pointer dereference in corrupted run #5: crashed: KASAN: use-after-free in padata_parallel_worker run #6: crashed: KASAN: use-after-free in padata_parallel_worker run #7: crashed: BUG: unable to handle kernel paging request in corrupted run #8: crashed: BUG: unable to handle kernel NULL pointer dereference in corrupted run #9: crashed: KASAN: use-after-free Write in padata_parallel_worker testing current HEAD ab9dfda232481dcfaf549ce774004d116fc80c13 testing commit ab9dfda232481dcfaf549ce774004d116fc80c13 with gcc (GCC) 8.1.0 kernel signature: 713615edff7289ecd6bd87ed6684dd8b656496b8dd39402f823e83c6eb1994c4 run #0: crashed: BUG: unable to handle kernel run #1: crashed: BUG: unable to handle kernel NULL pointer dereference in pcrypt_aead_serial run #2: crashed: KASAN: use-after-free Write in padata_parallel_worker run #3: crashed: BUG: unable to handle kernel NULL pointer dereference in pcrypt_aead_serial run #4: crashed: KASAN: use-after-free Write in padata_parallel_worker run #5: crashed: BUG: unable to handle kernel run #6: crashed: BUG: unable to handle kernel paging request in corrupted run #7: crashed: KASAN: use-after-free in padata_parallel_worker run #8: crashed: BUG: unable to handle kernel NULL pointer dereference in corrupted run #9: crashed: KASAN: use-after-free Write in padata_parallel_worker revisions tested: 2, total time: 25m24.243505743s (build: 18m1.322729476s, test: 5m58.338093047s) the crash still happens on HEAD commit msg: Linux 4.14.180 crash: KASAN: use-after-free Write in padata_parallel_worker TCP: request_sock_TCPv6: Possible SYN flooding on port 20002. Sending cookies. Check SNMP counters. bridge0: port 1(bridge_slave_0) entered blocking state bridge0: port 1(bridge_slave_0) entered forwarding state ================================================================== IPv6: ADDRCONF(NETDEV_CHANGE): veth1_to_hsr: link becomes ready BUG: KASAN: use-after-free in list_replace include/linux/list.h:141 [inline] BUG: KASAN: use-after-free in list_replace_init include/linux/list.h:149 [inline] BUG: KASAN: use-after-free in padata_parallel_worker+0x37a/0x420 kernel/padata.c:76 Write of size 8 at addr ffff8880938d2b98 by task kworker/0:2/3989 CPU: 0 PID: 3989 Comm: kworker/0:2 Not tainted 4.14.180-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 IPv6: ADDRCONF(NETDEV_CHANGE): hsr_slave_1: link becomes ready Workqueue: pencrypt padata_parallel_worker Call Trace: __dump_stack lib/dump_stack.c:17 [inline] dump_stack+0xf7/0x13b lib/dump_stack.c:58 print_address_description.cold.7+0x9/0x1c9 mm/kasan/report.c:252 kasan_report_error mm/kasan/report.c:351 [inline] kasan_report.cold.8+0x11a/0x2d3 mm/kasan/report.c:409 __asan_report_store8_noabort+0x17/0x20 mm/kasan/report.c:435 list_replace include/linux/list.h:141 [inline] list_replace_init include/linux/list.h:149 [inline] padata_parallel_worker+0x37a/0x420 kernel/padata.c:76 process_one_work+0x79e/0x16c0 kernel/workqueue.c:2116 worker_thread+0xcc/0xee0 kernel/workqueue.c:2250 kthread+0x338/0x400 kernel/kthread.c:232 IPv6: ADDRCONF(NETDEV_UP): veth1: link is not ready ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:404 Allocated by task 6992: save_stack_trace+0x16/0x20 arch/x86/kernel/stacktrace.c:59 save_stack+0x43/0xd0 mm/kasan/kasan.c:447 set_track mm/kasan/kasan.c:459 [inline] kasan_kmalloc+0xc7/0xe0 mm/kasan/kasan.c:551 __do_kmalloc mm/slab.c:3720 [inline] __kmalloc+0x15b/0x7b0 mm/slab.c:3729 kmalloc include/linux/slab.h:493 [inline] kzalloc include/linux/slab.h:661 [inline] tls_push_record+0xf6/0x14c0 net/tls/tls_sw.c:250 tls_sw_sendmsg+0x90b/0x10a0 net/tls/tls_sw.c:457 inet_sendmsg+0x108/0x440 net/ipv4/af_inet.c:762 sock_sendmsg_nosec net/socket.c:646 [inline] sock_sendmsg+0xb5/0xf0 net/socket.c:656 SYSC_sendto+0x1e3/0x2c0 net/socket.c:1763 SyS_sendto+0x9/0x10 net/socket.c:1731 do_syscall_64+0x1c7/0x5b0 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x42/0xb7 Freed by task 6992: save_stack_trace+0x16/0x20 arch/x86/kernel/stacktrace.c:59 save_stack+0x43/0xd0 mm/kasan/kasan.c:447 set_track mm/kasan/kasan.c:459 [inline] kasan_slab_free+0x71/0xc0 mm/kasan/kasan.c:524 __cache_free mm/slab.c:3496 [inline] kfree+0xcc/0x270 mm/slab.c:3815 tls_push_record+0xd32/0x14c0 net/tls/tls_sw.c:293 tls_sw_sendmsg+0x90b/0x10a0 net/tls/tls_sw.c:457 inet_sendmsg+0x108/0x440 net/ipv4/af_inet.c:762 sock_sendmsg_nosec net/socket.c:646 [inline] sock_sendmsg+0xb5/0xf0 net/socket.c:656 SYSC_sendto+0x1e3/0x2c0 net/socket.c:1763 SyS_sendto+0x9/0x10 net/socket.c:1731 do_syscall_64+0x1c7/0x5b0 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x42/0xb7 The buggy address belongs to the object at ffff8880938d2b40 which belongs to the cache kmalloc-256 of size 256 The buggy address is located 88 bytes inside of 256-byte region [ffff8880938d2b40, ffff8880938d2c40) The buggy address belongs to the page: page:ffffea00024e3480 count:1 mapcount:0 mapping:ffff8880938d2000 index:0x0 flags: 0x1fffc0000000100(slab) raw: 01fffc0000000100 ffff8880938d2000 0000000000000000 000000010000000c raw: ffffea0002437860 ffffea00024ad2e0 ffff8880aa8007c0 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff8880938d2a80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8880938d2b00: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb >ffff8880938d2b80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff8880938d2c00: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc ffff8880938d2c80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ==================================================================