================================================================== BUG: KASAN: use-after-free in bcm_can_tx+0x726/0x800 net/can/bcm.c:295 Read of size 4 at addr ffff8880924eb7c4 by task ksoftirqd/0/9 CPU: 0 PID: 9 Comm: ksoftirqd/0 Not tainted 4.19.211-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/12/2023 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x1fc/0x2ef lib/dump_stack.c:118 print_address_description.cold+0x54/0x219 mm/kasan/report.c:256 kasan_report_error.cold+0x8a/0x1b9 mm/kasan/report.c:354 kasan_report mm/kasan/report.c:412 [inline] __asan_report_load4_noabort+0x88/0x90 mm/kasan/report.c:432 bcm_can_tx+0x726/0x800 net/can/bcm.c:295 bcm_tx_timeout_tsklet+0x1f0/0x3a0 net/can/bcm.c:414 tasklet_action_common.constprop.0+0x265/0x360 kernel/softirq.c:522 __do_softirq+0x265/0x980 kernel/softirq.c:292 run_ksoftirqd+0x57/0x110 kernel/softirq.c:653 smpboot_thread_fn+0x655/0x9e0 kernel/smpboot.c:164 kthread+0x33f/0x460 kernel/kthread.c:259 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:415 Allocated by task 9966: kmem_cache_alloc_trace+0x12f/0x380 mm/slab.c:3625 kmalloc include/linux/slab.h:515 [inline] kzalloc include/linux/slab.h:709 [inline] bcm_tx_setup net/can/bcm.c:947 [inline] bcm_sendmsg+0x25d7/0x4150 net/can/bcm.c:1386 sock_sendmsg_nosec net/socket.c:651 [inline] sock_sendmsg+0xc3/0x120 net/socket.c:661 ___sys_sendmsg+0x7bb/0x8e0 net/socket.c:2227 __sys_sendmsg net/socket.c:2265 [inline] __do_sys_sendmsg net/socket.c:2274 [inline] __se_sys_sendmsg net/socket.c:2272 [inline] __x64_sys_sendmsg+0x132/0x220 net/socket.c:2272 do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe Freed by task 9966: __cache_free mm/slab.c:3503 [inline] kfree+0xcc/0x210 mm/slab.c:3822 bcm_release+0x260/0x950 net/can/bcm.c:1561 __sock_release+0xcd/0x2a0 net/socket.c:599 sock_close+0x15/0x20 net/socket.c:1214 __fput+0x2ce/0x890 fs/file_table.c:278 task_work_run+0x148/0x1c0 kernel/task_work.c:113 tracehook_notify_resume include/linux/tracehook.h:193 [inline] exit_to_usermode_loop+0x251/0x2a0 arch/x86/entry/common.c:167 prepare_exit_to_usermode arch/x86/entry/common.c:198 [inline] syscall_return_slowpath arch/x86/entry/common.c:271 [inline] do_syscall_64+0x538/0x620 arch/x86/entry/common.c:296 entry_SYSCALL_64_after_hwframe+0x49/0xbe The buggy address belongs to the object at ffff8880924eb680 which belongs to the cache kmalloc-1024 of size 1024 The buggy address is located 324 bytes inside of 1024-byte region [ffff8880924eb680, ffff8880924eba80) The buggy address belongs to the page: page:ffffea0002493a80 count:1 mapcount:0 mapping:ffff88813bff0ac0 index:0x0 compound_mapcount: 0 flags: 0xfff00000008100(slab|head) raw: 00fff00000008100 ffffea0002a7d588 ffffea0002a48608 ffff88813bff0ac0 raw: 0000000000000000 ffff8880924ea000 0000000100000007 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff8880924eb680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8880924eb700: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff8880924eb780: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff8880924eb800: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8880924eb880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================