bisecting fixing commit since 78e709522d2c012cb0daad2e668506637bffb7c2 building syzkaller on 5ae8508a2dd5f8e16a2b9830ae9a6f37d54ec8e7 testing commit 78e709522d2c012cb0daad2e668506637bffb7c2 compiler: gcc (GCC) 10.2.1 20210217, GNU ld (GNU Binutils for Debian) 2.35.2 kernel signature: a9ee8b045e5ead72fbe14b5ba3f27f4e7dade83d639c18306638c2a676910138 run #0: crashed: KASAN: use-after-free Write in null_skcipher_crypt run #1: crashed: KASAN: use-after-free Write in null_skcipher_crypt run #2: crashed: KASAN: use-after-free Write in null_skcipher_crypt run #3: crashed: KASAN: use-after-free Write in null_skcipher_crypt run #4: crashed: KASAN: slab-out-of-bounds Write in null_skcipher_crypt run #5: crashed: KASAN: use-after-free Write in null_skcipher_crypt run #6: crashed: KASAN: use-after-free Write in null_skcipher_crypt run #7: crashed: KASAN: use-after-free Write in null_skcipher_crypt run #8: crashed: KASAN: use-after-free Write in null_skcipher_crypt run #9: crashed: KASAN: use-after-free Write in null_skcipher_crypt run #10: crashed: KASAN: use-after-free Write in null_skcipher_crypt run #11: crashed: KASAN: use-after-free Write in null_skcipher_crypt run #12: crashed: KASAN: use-after-free Write in null_skcipher_crypt run #13: crashed: KASAN: use-after-free Write in null_skcipher_crypt run #14: crashed: KASAN: slab-out-of-bounds Write in null_skcipher_crypt run #15: crashed: KASAN: use-after-free Write in null_skcipher_crypt run #16: crashed: KASAN: use-after-free Write in null_skcipher_crypt run #17: crashed: KASAN: use-after-free Write in null_skcipher_crypt run #18: crashed: KASAN: use-after-free Write in null_skcipher_crypt run #19: crashed: KASAN: use-after-free Read in skb_copy_bits testing current HEAD debe436e77c72fcee804fb867f275e6d31aa999c testing commit debe436e77c72fcee804fb867f275e6d31aa999c compiler: gcc (GCC) 10.2.1 20210217, GNU ld (GNU Binutils for Debian) 2.35.2 kernel signature: a7de1bb2d0aff2b5805e7fb2ad50c41e721685bffda2aa859ebbb6b0332f862a run #0: crashed: KASAN: use-after-free Write in null_skcipher_crypt run #1: crashed: KASAN: slab-out-of-bounds Write in null_skcipher_crypt run #2: crashed: KASAN: use-after-free Write in null_skcipher_crypt run #3: crashed: KASAN: use-after-free Write in null_skcipher_crypt run #4: crashed: KASAN: use-after-free Write in null_skcipher_crypt run #5: crashed: KASAN: slab-out-of-bounds Write in null_skcipher_crypt run #6: crashed: KASAN: use-after-free Write in null_skcipher_crypt run #7: crashed: KASAN: use-after-free Write in null_skcipher_crypt run #8: crashed: KASAN: use-after-free Write in null_skcipher_crypt run #9: crashed: KASAN: use-after-free Write in null_skcipher_crypt revisions tested: 2, total time: 20m26.714615281s (build: 12m40.798786684s, test: 7m9.547502114s) the crash still happens on HEAD commit msg: Merge tag 'ext4_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4 crash: KASAN: use-after-free Write in null_skcipher_crypt ================================================================== BUG: KASAN: use-after-free in memcpy include/linux/fortify-string.h:225 [inline] BUG: KASAN: use-after-free in null_skcipher_crypt+0x8f/0xf0 crypto/crypto_null.c:85 Write of size 4096 at addr ffff888079490000 by task syz-executor.1/9051 CPU: 0 PID: 9051 Comm: syz-executor.1 Not tainted 5.15.0-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 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+0x8d/0x320 mm/kasan/report.c:247 __kasan_report mm/kasan/report.c:433 [inline] kasan_report.cold+0x83/0xdf mm/kasan/report.c:450 check_region_inline mm/kasan/generic.c:183 [inline] kasan_check_range+0x13d/0x180 mm/kasan/generic.c:189 memcpy+0x39/0x60 mm/kasan/shadow.c:66 memcpy include/linux/fortify-string.h:225 [inline] null_skcipher_crypt+0x8f/0xf0 crypto/crypto_null.c:85 crypto_authenc_encrypt+0x38b/0x530 crypto/authenc.c:222 esp6_output_tail+0x6de/0x1b60 net/ipv6/esp6.c:659 esp6_output+0x45d/0x910 net/ipv6/esp6.c:735 xfrm_output_one net/xfrm/xfrm_output.c:552 [inline] xfrm_output_resume+0x4ea/0x6110 net/xfrm/xfrm_output.c:587 NF_HOOK_COND include/linux/netfilter.h:296 [inline] xfrm6_output+0xe3/0x410 net/ipv6/xfrm6_output.c:92 ip6_send_skb+0x8f/0x2f0 net/ipv6/ip6_output.c:1912 rawv6_push_pending_frames net/ipv6/raw.c:613 [inline] rawv6_sendmsg+0x21d6/0x30c0 net/ipv6/raw.c:956 sock_sendmsg_nosec net/socket.c:704 [inline] sock_sendmsg+0xab/0xe0 net/socket.c:724 ____sys_sendmsg+0x5bf/0x7a0 net/socket.c:2409 ___sys_sendmsg+0xd3/0x150 net/socket.c:2463 __sys_sendmsg+0xb2/0x140 net/socket.c:2492 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 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:00007f32a8442188 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 000000000056bf80 RCX: 00000000004665f9 RDX: 0000000000000000 RSI: 0000000020000500 RDI: 0000000000000004 RBP: 00000000004bfcc4 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000056bf80 R13: 0000000000a9fb1f R14: 00007f32a8442300 R15: 0000000000022000 Allocated by task 10: kasan_save_stack+0x1e/0x50 mm/kasan/common.c:38 kasan_set_track mm/kasan/common.c:46 [inline] set_alloc_info mm/kasan/common.c:434 [inline] __kasan_slab_alloc+0x90/0xc0 mm/kasan/common.c:467 kasan_slab_alloc include/linux/kasan.h:259 [inline] slab_post_alloc_hook mm/slab.h:519 [inline] slab_alloc_node mm/slub.c:3234 [inline] kmem_cache_alloc_node+0x255/0x3f0 mm/slub.c:3270 alloc_task_struct_node kernel/fork.c:170 [inline] dup_task_struct kernel/fork.c:882 [inline] copy_process+0x468/0x6a40 kernel/fork.c:2023 kernel_clone+0xb8/0x7f0 kernel/fork.c:2581 kernel_thread+0xa3/0xe0 kernel/fork.c:2633 call_usermodehelper_exec_work kernel/umh.c:174 [inline] call_usermodehelper_exec_work+0xa4/0x140 kernel/umh.c:160 process_one_work+0x87f/0x1450 kernel/workqueue.c:2298 worker_thread+0x598/0x1040 kernel/workqueue.c:2445 kthread+0x3ab/0x480 kernel/kthread.c:327 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 Freed by task 7081: kasan_save_stack+0x1e/0x50 mm/kasan/common.c:38 kasan_set_track+0x21/0x30 mm/kasan/common.c:46 kasan_set_free_info+0x20/0x30 mm/kasan/generic.c:370 ____kasan_slab_free mm/kasan/common.c:366 [inline] ____kasan_slab_free mm/kasan/common.c:328 [inline] __kasan_slab_free+0xff/0x130 mm/kasan/common.c:374 kasan_slab_free include/linux/kasan.h:235 [inline] slab_free_hook mm/slub.c:1723 [inline] slab_free_freelist_hook+0x8b/0x1c0 mm/slub.c:1749 slab_free mm/slub.c:3513 [inline] kmem_cache_free+0x92/0x5e0 mm/slub.c:3529 rcu_do_batch kernel/rcu/tree.c:2506 [inline] rcu_core+0x7ab/0x1470 kernel/rcu/tree.c:2741 __do_softirq+0x29b/0x9c2 kernel/softirq.c:558 Last potentially related work creation: kasan_save_stack+0x1e/0x50 mm/kasan/common.c:38 __kasan_record_aux_stack+0xf5/0x120 mm/kasan/generic.c:348 __call_rcu kernel/rcu/tree.c:2985 [inline] call_rcu+0xb1/0x740 kernel/rcu/tree.c:3065 schedule_tail+0x7/0xd0 kernel/sched/core.c:4905 ret_from_fork+0x8/0x30 arch/x86/entry/entry_64.S:280 The buggy address belongs to the object at ffff888079490000 which belongs to the cache task_struct of size 7104 The buggy address is located 0 bytes inside of 7104-byte region [ffff888079490000, ffff888079491bc0) The buggy address belongs to the page: page:ffffea0001e52400 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x79490 head:ffffea0001e52400 order:3 compound_mapcount:0 compound_pincount:0 flags: 0xfff00000010200(slab|head|node=0|zone=1|lastcpupid=0x7ff) raw: 00fff00000010200 0000000000000000 dead000000000122 ffff888140006280 raw: 0000000000000000 0000000000040004 00000001ffffffff 0000000000000000 page dumped because: kasan: bad access detected page_owner tracks the page as allocated page last allocated via order 3, migratetype Unmovable, gfp_mask 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 10, ts 55002385402, free_ts 54985894027 prep_new_page mm/page_alloc.c:2418 [inline] get_page_from_freelist+0xa6f/0x2f10 mm/page_alloc.c:4149 __alloc_pages+0x1b2/0x500 mm/page_alloc.c:5369 alloc_slab_page mm/slub.c:1793 [inline] allocate_slab mm/slub.c:1930 [inline] new_slab+0x32d/0x4a0 mm/slub.c:1993 ___slab_alloc+0x91a/0xfd0 mm/slub.c:3022 __slab_alloc.constprop.0+0x4d/0xa0 mm/slub.c:3109 slab_alloc_node mm/slub.c:3200 [inline] kmem_cache_alloc_node+0x122/0x3f0 mm/slub.c:3270 alloc_task_struct_node kernel/fork.c:170 [inline] dup_task_struct kernel/fork.c:882 [inline] copy_process+0x468/0x6a40 kernel/fork.c:2023 kernel_clone+0xb8/0x7f0 kernel/fork.c:2581 kernel_thread+0xa3/0xe0 kernel/fork.c:2633 call_usermodehelper_exec_work kernel/umh.c:174 [inline] call_usermodehelper_exec_work+0xa4/0x140 kernel/umh.c:160 process_one_work+0x87f/0x1450 kernel/workqueue.c:2298 worker_thread+0x598/0x1040 kernel/workqueue.c:2445 kthread+0x3ab/0x480 kernel/kthread.c:327 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 page last free stack trace: reset_page_owner include/linux/page_owner.h:24 [inline] free_pages_prepare mm/page_alloc.c:1338 [inline] free_pcp_prepare+0x373/0x870 mm/page_alloc.c:1389 free_unref_page_prepare mm/page_alloc.c:3309 [inline] free_unref_page+0x19/0x690 mm/page_alloc.c:3388 __unfreeze_partials+0x343/0x360 mm/slub.c:2527 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+0xa2/0xc0 mm/kasan/common.c:444 kasan_slab_alloc include/linux/kasan.h:259 [inline] slab_post_alloc_hook mm/slab.h:519 [inline] slab_alloc_node mm/slub.c:3234 [inline] slab_alloc mm/slub.c:3242 [inline] __kmalloc+0x1e7/0x340 mm/slub.c:4419 kmalloc include/linux/slab.h:595 [inline] tomoyo_realpath_from_path+0xb0/0x6a0 security/tomoyo/realpath.c:254 tomoyo_get_realpath security/tomoyo/file.c:151 [inline] tomoyo_path_perm+0x1fb/0x350 security/tomoyo/file.c:822 security_inode_getattr+0xab/0x100 security/security.c:1334 vfs_getattr fs/stat.c:157 [inline] vfs_statx+0xe8/0x2e0 fs/stat.c:225 vfs_fstatat fs/stat.c:243 [inline] vfs_lstat include/linux/fs.h:3358 [inline] __do_sys_newlstat+0x85/0xe0 fs/stat.c:398 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae Memory state around the buggy address: ffff88807948ff00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ffff88807948ff80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 >ffff888079490000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff888079490080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888079490100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================