================================================================== BUG: KASAN: use-after-free in bcm_rx_starttimer net/can/bcm.c:543 [inline] BUG: KASAN: use-after-free in bcm_rx_handler+0x503/0x640 net/can/bcm.c:694 Read of size 4 at addr ffff888029a72418 by task syz-executor.1/11211 CPU: 0 PID: 11211 Comm: syz-executor.1 Not tainted 5.13.0-rc3-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:79 [inline] dump_stack+0xa5/0xe6 lib/dump_stack.c:120 print_address_description.constprop.0.cold+0x5b/0x2f8 mm/kasan/report.c:233 __kasan_report mm/kasan/report.c:419 [inline] kasan_report.cold+0x7c/0xd8 mm/kasan/report.c:436 bcm_rx_starttimer net/can/bcm.c:543 [inline] bcm_rx_handler+0x503/0x640 net/can/bcm.c:694 deliver net/can/af_can.c:574 [inline] can_rcv_filter+0x370/0x7b0 net/can/af_can.c:635 can_receive+0x239/0x490 net/can/af_can.c:661 can_rcv+0xce/0x150 net/can/af_can.c:696 __netif_receive_skb_one_core+0x104/0x180 net/core/dev.c:5459 process_backlog+0x1d2/0x610 net/core/dev.c:6437 __napi_poll+0x94/0x350 net/core/dev.c:6992 napi_poll net/core/dev.c:7059 [inline] net_rx_action+0x6fc/0xa50 net/core/dev.c:7146 __do_softirq+0x29b/0x9f6 kernel/softirq.c:559 do_softirq.part.0+0xd9/0x130 kernel/softirq.c:460 netif_rx_ni+0x22f/0x3c0 net/core/dev.c:4967 can_send+0x3ef/0x850 net/can/af_can.c:287 isotp_sendmsg+0x7e1/0x1530 net/can/isotp.c:948 sock_sendmsg_nosec net/socket.c:654 [inline] sock_sendmsg+0xab/0xe0 net/socket.c:674 ____sys_sendmsg+0x5bf/0x7a0 net/socket.c:2350 ___sys_sendmsg+0xd3/0x150 net/socket.c:2404 __sys_sendmsg+0xb2/0x140 net/socket.c:2433 do_syscall_64+0x3a/0xb0 arch/x86/entry/common.c:47 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x4665f9 Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 bc ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f852027e188 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 000000000056bf60 RCX: 00000000004665f9 RDX: 0000000000000004 RSI: 00000000200003c0 RDI: 0000000000000004 RBP: 00000000004bfce1 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000056bf60 R13: 00007ffe3f05a28f R14: 00007f852027e300 R15: 0000000000022000 Allocated by task 11232: kasan_save_stack+0x1b/0x40 mm/kasan/common.c:38 kasan_set_track mm/kasan/common.c:46 [inline] set_alloc_info mm/kasan/common.c:428 [inline] ____kasan_kmalloc mm/kasan/common.c:507 [inline] ____kasan_kmalloc mm/kasan/common.c:466 [inline] __kasan_kmalloc+0x9b/0xd0 mm/kasan/common.c:516 kmalloc include/linux/slab.h:556 [inline] kzalloc include/linux/slab.h:686 [inline] bcm_rx_setup net/can/bcm.c:1070 [inline] bcm_sendmsg+0x227f/0x4c10 net/can/bcm.c:1331 sock_sendmsg_nosec net/socket.c:654 [inline] sock_sendmsg+0xab/0xe0 net/socket.c:674 ____sys_sendmsg+0x5bf/0x7a0 net/socket.c:2350 ___sys_sendmsg+0xd3/0x150 net/socket.c:2404 __sys_sendmsg+0xb2/0x140 net/socket.c:2433 do_syscall_64+0x3a/0xb0 arch/x86/entry/common.c:47 entry_SYSCALL_64_after_hwframe+0x44/0xae Freed by task 11210: kasan_save_stack+0x1b/0x40 mm/kasan/common.c:38 kasan_set_track+0x1c/0x30 mm/kasan/common.c:46 kasan_set_free_info+0x20/0x30 mm/kasan/generic.c:357 ____kasan_slab_free mm/kasan/common.c:360 [inline] ____kasan_slab_free mm/kasan/common.c:325 [inline] __kasan_slab_free+0xfb/0x130 mm/kasan/common.c:368 kasan_slab_free include/linux/kasan.h:212 [inline] slab_free_hook mm/slub.c:1582 [inline] slab_free_freelist_hook+0xdf/0x240 mm/slub.c:1607 slab_free mm/slub.c:3167 [inline] kfree+0xe5/0x7f0 mm/slub.c:4217 bcm_release+0x2a6/0x670 net/can/bcm.c:1506 __sock_release+0xbb/0x270 net/socket.c:599 sock_close+0xf/0x20 net/socket.c:1258 __fput+0x209/0x870 fs/file_table.c:280 task_work_run+0xc0/0x160 kernel/task_work.c:164 tracehook_notify_resume include/linux/tracehook.h:189 [inline] exit_to_user_mode_loop kernel/entry/common.c:174 [inline] exit_to_user_mode_prepare+0x272/0x280 kernel/entry/common.c:208 __syscall_exit_to_user_mode_work kernel/entry/common.c:290 [inline] syscall_exit_to_user_mode+0x19/0x60 kernel/entry/common.c:301 do_syscall_64+0x47/0xb0 arch/x86/entry/common.c:57 entry_SYSCALL_64_after_hwframe+0x44/0xae The buggy address belongs to the object at ffff888029a72400 which belongs to the cache kmalloc-512 of size 512 The buggy address is located 24 bytes inside of 512-byte region [ffff888029a72400, ffff888029a72600) The buggy address belongs to the page: page:ffffea0000a69c00 refcount:1 mapcount:0 mapping:0000000000000000 index:0xffff888029a73800 pfn:0x29a70 head:ffffea0000a69c00 order:2 compound_mapcount:0 compound_pincount:0 flags: 0xfff00000010200(slab|head|node=0|zone=1|lastcpupid=0x7ff) raw: 00fff00000010200 ffffea00007d7200 0000000300000003 ffff88800f841c80 raw: ffff888029a73800 000000008010000f 00000001ffffffff 0000000000000000 page dumped because: kasan: bad access detected page_owner tracks the page as allocated page last allocated via order 2, migratetype Unmovable, gfp_mask 0xd28c0(GFP_NOWAIT|__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 8851, ts 68155797487, free_ts 68104611082 prep_new_page mm/page_alloc.c:2358 [inline] get_page_from_freelist+0x1034/0x2bf0 mm/page_alloc.c:3994 __alloc_pages+0x1b2/0x500 mm/page_alloc.c:5200 alloc_slab_page mm/slub.c:1645 [inline] allocate_slab+0x32e/0x4c0 mm/slub.c:1785 new_slab mm/slub.c:1848 [inline] new_slab_objects mm/slub.c:2594 [inline] ___slab_alloc+0x4a1/0x810 mm/slub.c:2757 __slab_alloc.constprop.0+0xa7/0xf0 mm/slub.c:2797 slab_alloc_node mm/slub.c:2879 [inline] __kmalloc_node_track_caller+0x2e6/0x350 mm/slub.c:4596 kmalloc_reserve net/core/skbuff.c:355 [inline] pskb_expand_head+0x11f/0xf50 net/core/skbuff.c:1682 netlink_trim+0x18f/0x1f0 net/netlink/af_netlink.c:1296 netlink_broadcast_filtered+0x58/0xac0 net/netlink/af_netlink.c:1501 netlink_broadcast net/netlink/af_netlink.c:1546 [inline] nlmsg_multicast include/net/netlink.h:1033 [inline] nlmsg_notify+0x60/0x1b0 net/netlink/af_netlink.c:2547 rtmsg_fib+0x2be/0x450 net/ipv4/fib_semantics.c:532 fib_table_insert+0x661/0x1f10 net/ipv4/fib_trie.c:1389 fib_magic+0x2f5/0x460 net/ipv4/fib_frontend.c:1085 fib_inetaddr_event+0x13a/0x260 net/ipv4/fib_frontend.c:1418 notifier_call_chain+0x94/0x170 kernel/notifier.c:83 blocking_notifier_call_chain kernel/notifier.c:337 [inline] blocking_notifier_call_chain+0x5d/0x80 kernel/notifier.c:325 page last free stack trace: reset_page_owner include/linux/page_owner.h:24 [inline] free_pages_prepare mm/page_alloc.c:1298 [inline] __free_pages_ok+0x476/0xce0 mm/page_alloc.c:1572 unfreeze_partials+0x17c/0x1d0 mm/slub.c:2375 put_cpu_partial+0x13d/0x230 mm/slub.c:2411 qlink_free mm/kasan/quarantine.c:146 [inline] qlist_free_all+0x5a/0xc0 mm/kasan/quarantine.c:165 kasan_quarantine_reduce+0x180/0x200 mm/kasan/quarantine.c:272 __kasan_slab_alloc+0x8e/0xa0 mm/kasan/common.c:438 kasan_slab_alloc include/linux/kasan.h:236 [inline] slab_post_alloc_hook mm/slab.h:524 [inline] slab_alloc_node mm/slub.c:2913 [inline] slab_alloc mm/slub.c:2921 [inline] kmem_cache_alloc+0x219/0x3a0 mm/slub.c:2926 getname_flags.part.0+0x4a/0x440 fs/namei.c:138 do_sys_openat2+0xd2/0x360 fs/open.c:1181 do_sys_open fs/open.c:1203 [inline] __do_sys_open fs/open.c:1211 [inline] __se_sys_open fs/open.c:1207 [inline] __x64_sys_open+0xfd/0x1a0 fs/open.c:1207 do_syscall_64+0x3a/0xb0 arch/x86/entry/common.c:47 entry_SYSCALL_64_after_hwframe+0x44/0xae Memory state around the buggy address: ffff888029a72300: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff888029a72380: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff888029a72400: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff888029a72480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888029a72500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================