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 consume_skb run #6: crashed: KASAN: use-after-free Read in consume_skb run #7: crashed: KASAN: use-after-free Read in sk_psock_backlog run #8: crashed: KASAN: use-after-free Read in consume_skb 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 30306f6194cadcc29c77f6ddcd416a75bf5c0232 testing commit 30306f6194cadcc29c77f6ddcd416a75bf5c0232 compiler: gcc (GCC) 10.2.1 20210217, GNU ld (GNU Binutils for Debian) 2.35.2 kernel signature: e3b47520f3b6864f981344925a72e4213c5a1623a14122e6930745508255645e 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 revisions tested: 2, total time: 21m17.208143359s (build: 13m31.851033482s, test: 6m47.351240773s) the crash still happens on HEAD commit msg: Merge tag 'hardening-v5.19-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux crash: KASAN: use-after-free Read in consume_skb IPv6: ADDRCONF(NETDEV_CHANGE): wlan1: link becomes ready ================================================================== 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:1359 [inline] BUG: KASAN: use-after-free in consume_skb+0x23/0xf0 net/core/skbuff.c:913 Read of size 4 at addr ffff88801aaf135c by task kworker/0:2/141 CPU: 0 PID: 141 Comm: kworker/0:2 Not tainted 5.19.0-rc2-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:1359 [inline] consume_skb+0x23/0xf0 net/core/skbuff.c:913 __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:761 [inline] __sk_psock_zap_ingress net/core/skmsg.c:779 [inline] sk_psock_stop+0x3f3/0x640 net/core/skmsg.c:797 sk_psock_drop+0x14f/0x350 net/core/skmsg.c:839 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:1150 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:302 Allocated by task 4130: 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:750 [inline] slab_alloc_node mm/slub.c:3214 [inline] slab_alloc mm/slub.c:3222 [inline] __kmem_cache_alloc_lru mm/slub.c:3229 [inline] kmem_cache_alloc+0x204/0x3b0 mm/slub.c:3239 skb_clone+0x11c/0x2f0 net/core/skbuff.c:1515 sk_psock_verdict_recv+0x48/0x610 net/core/skmsg.c:1172 unix_read_sock+0xc4/0x1e0 net/unix/af_unix.c:2506 sk_psock_verdict_data_ready+0xf8/0x150 net/core/skmsg.c:1215 unix_dgram_sendmsg+0xcc5/0x1790 net/unix/af_unix.c:2028 sock_sendmsg_nosec net/socket.c:714 [inline] sock_sendmsg+0xab/0xe0 net/socket.c:734 ____sys_sendmsg+0x395/0x7a0 net/socket.c:2492 ___sys_sendmsg+0xd3/0x150 net/socket.c:2546 __sys_sendmmsg+0x141/0x310 net/socket.c:2632 __do_sys_sendmmsg net/socket.c:2661 [inline] __se_sys_sendmmsg net/socket.c:2658 [inline] __x64_sys_sendmmsg+0x94/0x100 net/socket.c:2658 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+0x46/0xb0 Freed by task 141: 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:1727 [inline] slab_free_freelist_hook+0x8b/0x1c0 mm/slub.c:1753 slab_free mm/slub.c:3507 [inline] kmem_cache_free+0xdd/0x5a0 mm/slub.c:3524 kfree_skb include/linux/skbuff.h:1375 [inline] sock_drop include/linux/skmsg.h:304 [inline] sk_psock_backlog+0x871/0xd20 net/core/skmsg.c:681 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:302 The buggy address belongs to the object at ffff88801aaf1280 which belongs to the cache skbuff_head_cache of size 232 The buggy address is located 220 bytes inside of 232-byte region [ffff88801aaf1280, ffff88801aaf1368) The buggy address belongs to the physical page: page:ffffea00006abc40 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x1aaf1 memcg:ffff888020b03681 flags: 0xfff00000000200(slab|node=0|zone=1|lastcpupid=0x7ff) raw: 00fff00000000200 ffffea0001d8d000 dead000000000007 ffff8881401c4140 raw: 0000000000000000 00000000000c000c 00000001ffffffff ffff888020b03681 page dumped because: kasan: bad access detected page_owner tracks the page as allocated page last allocated via order 0, migratetype Unmovable, gfp_mask 0x112a20(GFP_ATOMIC|__GFP_NOWARN|__GFP_NORETRY|__GFP_HARDWALL), pid 1444, tgid 1444 (kworker/u4:6), ts 42903823204, free_ts 42789079590 prep_new_page mm/page_alloc.c:2456 [inline] get_page_from_freelist+0x19d3/0x3b30 mm/page_alloc.c:4198 __alloc_pages+0x1c7/0x510 mm/page_alloc.c:5426 alloc_slab_page mm/slub.c:1797 [inline] allocate_slab+0x26c/0x3c0 mm/slub.c:1942 new_slab mm/slub.c:2002 [inline] ___slab_alloc+0x950/0xd90 mm/slub.c:3002 __slab_alloc.constprop.0+0x4d/0xa0 mm/slub.c:3089 slab_alloc_node mm/slub.c:3180 [inline] kmem_cache_alloc_node+0x122/0x3f0 mm/slub.c:3264 __alloc_skb+0x151/0x270 net/core/skbuff.c:414 alloc_skb include/linux/skbuff.h:1426 [inline] nlmsg_new include/net/netlink.h:953 [inline] __neigh_notify+0x7f/0x120 net/core/neighbour.c:3459 neigh_cleanup_and_release+0x5a/0x220 net/core/neighbour.c:101 neigh_flush_dev+0x4a4/0x7b0 net/core/neighbour.c:369 __neigh_ifdown.isra.0+0x44/0x3c0 net/core/neighbour.c:386 neigh_ifdown+0x7/0x10 net/core/neighbour.c:403 rt6_disable_ip+0x59e/0x800 net/ipv6/route.c:4894 addrconf_ifdown.isra.0+0xea/0x1350 net/ipv6/addrconf.c:3750 addrconf_notify+0x387/0x15a0 net/ipv6/addrconf.c:3673 notifier_call_chain+0x94/0x170 kernel/notifier.c:87 page last free stack trace: reset_page_owner include/linux/page_owner.h:24 [inline] free_pages_prepare mm/page_alloc.c:1371 [inline] free_pcp_prepare+0x549/0xd20 mm/page_alloc.c:1421 free_unref_page_prepare mm/page_alloc.c:3343 [inline] free_unref_page_list+0x16f/0xf80 mm/page_alloc.c:3475 release_pages+0x6f1/0x1780 mm/swap.c:980 tlb_batch_pages_flush+0x85/0x160 mm/mmu_gather.c:58 tlb_flush_mmu_free mm/mmu_gather.c:255 [inline] tlb_flush_mmu mm/mmu_gather.c:262 [inline] tlb_finish_mmu+0x110/0x6c0 mm/mmu_gather.c:353 exit_mmap+0x19d/0x3f0 mm/mmap.c:3164 __mmput+0xed/0x430 kernel/fork.c:1187 exit_mm kernel/exit.c:510 [inline] do_exit+0x8e9/0x2470 kernel/exit.c:782 do_group_exit+0xb2/0x2a0 kernel/exit.c:925 __do_sys_exit_group kernel/exit.c:936 [inline] __se_sys_exit_group kernel/exit.c:934 [inline] __x64_sys_exit_group+0x35/0x40 kernel/exit.c:934 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+0x46/0xb0 Memory state around the buggy address: ffff88801aaf1200: fb fb fb fb fb fc fc fc fc fc fc fc fc fc fc fc ffff88801aaf1280: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff88801aaf1300: fb fb fb fb fb fb fb fb fb fb fb fb fb fc fc fc ^ ffff88801aaf1380: fc fc fc fc fc fc fc fc fa fb fb fb fb fb fb fb ffff88801aaf1400: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================