bisecting fixing commit since 7fd2bf83d59a2d32e0d596c5d3e623b9a0e7e2d5 building syzkaller on 838e7e2cd9228583ca33c49a39aea4d863d3e36d testing commit 7fd2bf83d59a2d32e0d596c5d3e623b9a0e7e2d5 compiler: gcc (GCC) 10.2.1 20210217, GNU ld (GNU Binutils for Debian) 2.35.2 kernel signature: 1ea94d1a92e7d49dc3d6a449c0bbea04cb19022e1787c51b44fd2f33eba59b87 run #0: crashed: KASAN: use-after-free Read in consume_skb run #1: crashed: KASAN: use-after-free Read in consume_skb run #2: crashed: KASAN: use-after-free Read in consume_skb run #3: crashed: KASAN: use-after-free Read in consume_skb run #4: crashed: KASAN: use-after-free Read in consume_skb run #5: crashed: KASAN: use-after-free Read in sk_psock_backlog run #6: crashed: KASAN: use-after-free Read in consume_skb run #7: crashed: KASAN: use-after-free Read in consume_skb run #8: crashed: KASAN: use-after-free Read in sk_psock_backlog run #9: crashed: KASAN: use-after-free Read in consume_skb run #10: crashed: KASAN: use-after-free Read in consume_skb run #11: crashed: KASAN: use-after-free Read in consume_skb run #12: crashed: KASAN: use-after-free Read in consume_skb run #13: crashed: KASAN: use-after-free Read in consume_skb run #14: crashed: KASAN: use-after-free Read in consume_skb run #15: crashed: KASAN: use-after-free Read in consume_skb run #16: crashed: KASAN: use-after-free Read in consume_skb run #17: crashed: KASAN: use-after-free Read in consume_skb run #18: crashed: KASAN: use-after-free Read in consume_skb run #19: crashed: KASAN: use-after-free Read in consume_skb testing current HEAD 42226c989789d8da4af1de0c31070c96726d990c testing commit 42226c989789d8da4af1de0c31070c96726d990c compiler: gcc (GCC) 10.2.1 20210217, GNU ld (GNU Binutils for Debian) 2.35.2 kernel signature: 08de8268ae31d8fee687b9ddd36a8eb745dee8fdb0642293cabebd809d1119d4 all runs: crashed: KASAN: use-after-free Read in consume_skb revisions tested: 2, total time: 19m26.124990468s (build: 12m11.518217306s, test: 6m22.529340925s) the crash still happens on HEAD commit msg: Linux 5.18-rc7 crash: KASAN: use-after-free Read in consume_skb ================================================================== BUG: KASAN: use-after-free in instrument_atomic_read include/linux/instrumented.h:71 [inline] BUG: KASAN: use-after-free in atomic_read include/linux/atomic/atomic-instrumented.h:27 [inline] BUG: KASAN: use-after-free in refcount_read include/linux/refcount.h:147 [inline] BUG: KASAN: use-after-free in skb_unref include/linux/skbuff.h:1234 [inline] BUG: KASAN: use-after-free in consume_skb+0x23/0xf0 net/core/skbuff.c:911 Read of size 4 at addr ffff888021b86994 by task kworker/1:2/138 CPU: 1 PID: 138 Comm: kworker/1:2 Not tainted 5.18.0-rc7-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: events bpf_map_free_deferred Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x57/0x7d lib/dump_stack.c:106 print_address_description.constprop.0.cold+0xeb/0x495 mm/kasan/report.c:313 print_report mm/kasan/report.c:429 [inline] kasan_report.cold+0xf4/0x1c6 mm/kasan/report.c:491 check_region_inline mm/kasan/generic.c:183 [inline] kasan_check_range+0x13d/0x180 mm/kasan/generic.c:189 instrument_atomic_read include/linux/instrumented.h:71 [inline] atomic_read include/linux/atomic/atomic-instrumented.h:27 [inline] refcount_read include/linux/refcount.h:147 [inline] skb_unref include/linux/skbuff.h:1234 [inline] consume_skb+0x23/0xf0 net/core/skbuff.c:911 __sk_msg_free+0x198/0x340 net/core/skmsg.c:205 sk_msg_free net/core/skmsg.c:218 [inline] __sk_psock_purge_ingress_msg net/core/skmsg.c:757 [inline] __sk_psock_zap_ingress net/core/skmsg.c:775 [inline] sk_psock_stop+0x3f3/0x640 net/core/skmsg.c:793 sk_psock_drop+0x14f/0x350 net/core/skmsg.c:835 sk_psock_put include/linux/skmsg.h:450 [inline] sock_map_unref net/core/sock_map.c:185 [inline] sock_hash_free+0x53f/0x730 net/core/sock_map.c:1151 process_one_work+0x865/0x13d0 kernel/workqueue.c:2289 worker_thread+0x598/0xec0 kernel/workqueue.c:2436 kthread+0x299/0x340 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:298 Allocated by task 4119: kasan_save_stack+0x1e/0x40 mm/kasan/common.c:38 kasan_set_track mm/kasan/common.c:45 [inline] set_alloc_info mm/kasan/common.c:436 [inline] __kasan_slab_alloc+0x90/0xc0 mm/kasan/common.c:469 kasan_slab_alloc include/linux/kasan.h:224 [inline] slab_post_alloc_hook mm/slab.h:749 [inline] slab_alloc_node mm/slub.c:3217 [inline] slab_alloc mm/slub.c:3225 [inline] __kmem_cache_alloc_lru mm/slub.c:3232 [inline] kmem_cache_alloc+0x204/0x3b0 mm/slub.c:3242 skb_clone+0x125/0x300 net/core/skbuff.c:1520 sk_psock_verdict_recv+0x48/0x610 net/core/skmsg.c:1168 unix_read_sock+0xc4/0x1e0 net/unix/af_unix.c:2508 sk_psock_verdict_data_ready+0xf8/0x150 net/core/skmsg.c:1211 unix_dgram_sendmsg+0xca6/0x1770 net/unix/af_unix.c:2029 sock_sendmsg_nosec net/socket.c:705 [inline] sock_sendmsg+0xab/0xe0 net/socket.c:725 ____sys_sendmsg+0x38c/0x7a0 net/socket.c:2413 ___sys_sendmsg+0xd3/0x150 net/socket.c:2467 __sys_sendmmsg+0x141/0x310 net/socket.c:2553 __do_sys_sendmmsg net/socket.c:2582 [inline] __se_sys_sendmmsg net/socket.c:2579 [inline] __x64_sys_sendmmsg+0x94/0x100 net/socket.c:2579 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x35/0x80 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae Freed by task 6: kasan_save_stack+0x1e/0x40 mm/kasan/common.c:38 kasan_set_track+0x21/0x30 mm/kasan/common.c:45 kasan_set_free_info+0x20/0x30 mm/kasan/generic.c:370 ____kasan_slab_free mm/kasan/common.c:366 [inline] ____kasan_slab_free+0x166/0x1a0 mm/kasan/common.c:328 kasan_slab_free include/linux/kasan.h:200 [inline] slab_free_hook mm/slub.c:1728 [inline] slab_free_freelist_hook+0x8b/0x1c0 mm/slub.c:1754 slab_free mm/slub.c:3510 [inline] kmem_cache_free+0xdd/0x5a0 mm/slub.c:3527 kfree_skb include/linux/skbuff.h:1250 [inline] sock_drop include/linux/skmsg.h:304 [inline] sk_psock_backlog+0x871/0xd20 net/core/skmsg.c:677 process_one_work+0x865/0x13d0 kernel/workqueue.c:2289 worker_thread+0x598/0xec0 kernel/workqueue.c:2436 kthread+0x299/0x340 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:298 The buggy address belongs to the object at ffff888021b868c0 which belongs to the cache skbuff_head_cache of size 224 The buggy address is located 212 bytes inside of 224-byte region [ffff888021b868c0, ffff888021b869a0) The buggy address belongs to the physical page: page:ffffea000086e180 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x21b86 memcg:ffff88801e14e781 flags: 0xfff00000000200(slab|node=0|zone=1|lastcpupid=0x7ff) raw: 00fff00000000200 0000000000000000 dead000000000122 ffff888010b86140 raw: 0000000000000000 00000000000c000c 00000001ffffffff ffff88801e14e781 page dumped because: kasan: bad access detected page_owner tracks the page as allocated page last allocated via order 0, migratetype Unmovable, gfp_mask 0x112cc0(GFP_USER|__GFP_NOWARN|__GFP_NORETRY), pid 4117, tgid 4116 (syz-executor.0), ts 64837546480, free_ts 64124235457 prep_new_page mm/page_alloc.c:2441 [inline] get_page_from_freelist+0x178d/0x3dc0 mm/page_alloc.c:4182 __alloc_pages+0x1b2/0x500 mm/page_alloc.c:5408 alloc_slab_page mm/slub.c:1799 [inline] allocate_slab+0x26c/0x3c0 mm/slub.c:1944 new_slab mm/slub.c:2004 [inline] ___slab_alloc+0x8e1/0xf20 mm/slub.c:3005 __slab_alloc.constprop.0+0x4d/0xa0 mm/slub.c:3092 slab_alloc_node mm/slub.c:3183 [inline] kmem_cache_alloc_node+0x122/0x3f0 mm/slub.c:3267 __alloc_skb+0x151/0x270 net/core/skbuff.c:414 alloc_skb include/linux/skbuff.h:1300 [inline] alloc_skb_with_frags+0x72/0x700 net/core/skbuff.c:5997 sock_alloc_send_pskb+0x636/0x7c0 net/core/sock.c:2600 unix_dgram_sendmsg+0x35a/0x1770 net/unix/af_unix.c:1896 sock_sendmsg_nosec net/socket.c:705 [inline] sock_sendmsg+0xab/0xe0 net/socket.c:725 ____sys_sendmsg+0x38c/0x7a0 net/socket.c:2413 ___sys_sendmsg+0xd3/0x150 net/socket.c:2467 __sys_sendmmsg+0x141/0x310 net/socket.c:2553 __do_sys_sendmmsg net/socket.c:2582 [inline] __se_sys_sendmmsg net/socket.c:2579 [inline] __x64_sys_sendmmsg+0x94/0x100 net/socket.c:2579 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x35/0x80 arch/x86/entry/common.c:80 page last free stack trace: reset_page_owner include/linux/page_owner.h:24 [inline] free_pages_prepare mm/page_alloc.c:1356 [inline] free_pcp_prepare+0x549/0xd20 mm/page_alloc.c:1406 free_unref_page_prepare mm/page_alloc.c:3328 [inline] free_unref_page+0x19/0x6a0 mm/page_alloc.c:3423 __unfreeze_partials+0x17c/0x1a0 mm/slub.c:2523 qlink_free mm/kasan/quarantine.c:157 [inline] qlist_free_all+0x6a/0x170 mm/kasan/quarantine.c:176 kasan_quarantine_reduce+0x180/0x200 mm/kasan/quarantine.c:283 __kasan_slab_alloc+0xa2/0xc0 mm/kasan/common.c:446 kasan_slab_alloc include/linux/kasan.h:224 [inline] slab_post_alloc_hook mm/slab.h:749 [inline] slab_alloc_node mm/slub.c:3217 [inline] slab_alloc mm/slub.c:3225 [inline] __kmalloc+0x200/0x350 mm/slub.c:4410 kmalloc include/linux/slab.h:586 [inline] tomoyo_add_entry security/tomoyo/common.c:2022 [inline] tomoyo_supervisor+0xa4b/0xc40 security/tomoyo/common.c:2094 tomoyo_audit_path_number_log security/tomoyo/file.c:235 [inline] tomoyo_path_number_perm+0x38a/0x4d0 security/tomoyo/file.c:734 security_file_ioctl+0x44/0x80 security/security.c:1557 __do_sys_ioctl fs/ioctl.c:864 [inline] __se_sys_ioctl fs/ioctl.c:856 [inline] __x64_sys_ioctl+0x99/0x190 fs/ioctl.c:856 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x35/0x80 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae Memory state around the buggy address: ffff888021b86880: fc fc fc fc fc fc fc fc fa fb fb fb fb fb fb fb ffff888021b86900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff888021b86980: fb fb fb fb fc fc fc fc fc fc fc fc fc fc fc fc ^ ffff888021b86a00: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888021b86a80: fb fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc ==================================================================