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BUG: KASAN: use-after-free in tasklet_action+0x29f/0x340 kernel/softirq.c:506
Read of size 8 at addr ffff8880b348ea10 by task systemd-udevd/31927

CPU: 1 PID: 31927 Comm: systemd-udevd Not tainted 4.14.263-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 <IRQ>
 __dump_stack lib/dump_stack.c:17 [inline]
 dump_stack+0x1b2/0x281 lib/dump_stack.c:58
 print_address_description.cold+0x54/0x1d3 mm/kasan/report.c:252
 kasan_report_error.cold+0x8a/0x191 mm/kasan/report.c:351
 kasan_report mm/kasan/report.c:409 [inline]
 __asan_report_load8_noabort+0x68/0x70 mm/kasan/report.c:430
 tasklet_action+0x29f/0x340 kernel/softirq.c:506
 __do_softirq+0x24d/0x9ff kernel/softirq.c:288
 invoke_softirq kernel/softirq.c:368 [inline]
 irq_exit+0x193/0x240 kernel/softirq.c:409
 exiting_irq arch/x86/include/asm/apic.h:638 [inline]
 smp_apic_timer_interrupt+0x141/0x5e0 arch/x86/kernel/apic/apic.c:1106
 apic_timer_interrupt+0x93/0xa0 arch/x86/entry/entry_64.S:793
 </IRQ>
RIP: 0010:__sanitizer_cov_trace_pc+0x23/0x50 kernel/kcov.c:68
RSP: 0000:ffff88809ca57bb0 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff10
RAX: ffff8880b4f54240 RBX: dffffc0000000000 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 00000000ffffffff RDI: ffffea00001dbda0
RBP: ffffea00001dbd80 R08: ffff88809ca57db8 R09: 0000000000000003
R10: 0000000000000000 R11: ffff8880b4f54240 R12: ffffea00001dbd80
R13: ffffea00001dbd9c R14: ffff8880b1f9b090 R15: ffffea00001dbd60
 __read_once_size include/linux/compiler.h:185 [inline]
 compound_head include/linux/page-flags.h:147 [inline]
 trylock_page include/linux/pagemap.h:469 [inline]
 filemap_map_pages+0x6eb/0xe40 mm/filemap.c:2572
 do_fault_around+0x1fe/0x620 mm/memory.c:3697
 do_read_fault mm/memory.c:3731 [inline]
 do_fault mm/memory.c:3862 [inline]
 handle_pte_fault mm/memory.c:4092 [inline]
 __handle_mm_fault+0x2b1f/0x4620 mm/memory.c:4216
 handle_mm_fault+0x455/0x9c0 mm/memory.c:4253
 __do_page_fault+0x549/0xad0 arch/x86/mm/fault.c:1442
 page_fault+0x45/0x50 arch/x86/entry/entry_64.S:1123
RIP: 0000:0x7fcb9ac27b58
RSP: 9ac289e0:0000000000000003 EFLAGS: 0000000d

Allocated by task 31919:
 save_stack mm/kasan/kasan.c:447 [inline]
 set_track mm/kasan/kasan.c:459 [inline]
 kasan_kmalloc+0xeb/0x160 mm/kasan/kasan.c:551
 kmem_cache_alloc_trace+0x131/0x3d0 mm/slab.c:3618
 kmalloc include/linux/slab.h:488 [inline]
 kzalloc include/linux/slab.h:661 [inline]
 bcm_tx_setup net/can/bcm.c:960 [inline]
 bcm_sendmsg+0x20bb/0x3ae0 net/can/bcm.c:1396
 sock_sendmsg_nosec net/socket.c:646 [inline]
 sock_sendmsg+0xb5/0x100 net/socket.c:656
 ___sys_sendmsg+0x6c8/0x800 net/socket.c:2062
 __sys_sendmsg+0xa3/0x120 net/socket.c:2096
 SYSC_sendmsg net/socket.c:2107 [inline]
 SyS_sendmsg+0x27/0x40 net/socket.c:2103
 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x46/0xbb

Freed by task 31917:
 save_stack mm/kasan/kasan.c:447 [inline]
 set_track mm/kasan/kasan.c:459 [inline]
 kasan_slab_free+0xc3/0x1a0 mm/kasan/kasan.c:524
 __cache_free mm/slab.c:3496 [inline]
 kfree+0xc9/0x250 mm/slab.c:3815
 bcm_release+0x255/0x900 net/can/bcm.c:1571
 __sock_release+0xcd/0x2b0 net/socket.c:602
 sock_close+0x15/0x20 net/socket.c:1139
 __fput+0x25f/0x7a0 fs/file_table.c:210
 task_work_run+0x11f/0x190 kernel/task_work.c:113
 tracehook_notify_resume include/linux/tracehook.h:191 [inline]
 exit_to_usermode_loop+0x1ad/0x200 arch/x86/entry/common.c:164
 prepare_exit_to_usermode arch/x86/entry/common.c:199 [inline]
 syscall_return_slowpath arch/x86/entry/common.c:270 [inline]
 do_syscall_64+0x4a3/0x640 arch/x86/entry/common.c:297
 entry_SYSCALL_64_after_hwframe+0x46/0xbb

The buggy address belongs to the object at ffff8880b348e940
 which belongs to the cache kmalloc-1024 of size 1024
The buggy address is located 208 bytes inside of
 1024-byte region [ffff8880b348e940, ffff8880b348ed40)
The buggy address belongs to the page:
page:ffffea0002cd2380 count:1 mapcount:0 mapping:ffff8880b348e040 index:0xffff8880b348e040 compound_mapcount: 0
flags: 0xfff00000008100(slab|head)
raw: 00fff00000008100 ffff8880b348e040 ffff8880b348e040 0000000100000004
raw: ffffea0002d15ca0 ffffea0002730d20 ffff88813fe74ac0 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8880b348e900: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb
 ffff8880b348e980: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff8880b348ea00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                         ^
 ffff8880b348ea80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8880b348eb00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
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