Hello, syzbot found the following crash on: HEAD commit: fdfa3a67 Merge tag 'scsi-misc' of git://git.kernel.org/pub.. git tree: net-next console output: https://syzkaller.appspot.com/x/log.txt?x=17d4c07ee00000 kernel config: https://syzkaller.appspot.com/x/.config?x=71f1d0a1df5278ab dashboard link: https://syzkaller.appspot.com/bug?extid=6ef7546f7398f3f97609 compiler: gcc (GCC) 9.0.0 20181231 (experimental) Unfortunately, I don't have any reproducer for this crash yet. IMPORTANT: if you fix the bug, please add the following tag to the commit: Reported-by: syzbot+6ef7546f7398f3f97609@xxxxxxxxxxxxxxxxxxxxxxxxx ================================================================== BUG: KASAN: use-after-free in __list_del_entry_valid+0xdc/0xf5 lib/list_debug.c:54 Read of size 8 at addr ffff888096b35650 by task syz-executor.2/16535 CPU: 0 PID: 16535 Comm: syz-executor.2 Not tainted 5.5.0-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x197/0x210 lib/dump_stack.c:118 print_address_description.constprop.0.cold+0xd4/0x30b mm/kasan/report.c:374 __kasan_report.cold+0x1b/0x32 mm/kasan/report.c:506 kasan_report+0x12/0x20 mm/kasan/common.c:641 __asan_report_load8_noabort+0x14/0x20 mm/kasan/generic_report.c:135 __list_del_entry_valid+0xdc/0xf5 lib/list_debug.c:54 __list_del_entry include/linux/list.h:132 [inline] list_del_init include/linux/list.h:204 [inline] inode_io_list_del_locked+0x8b/0x200 fs/fs-writeback.c:148 inode_io_list_del+0x32/0x40 fs/fs-writeback.c:1126 evict+0x11d/0x680 fs/inode.c:562 iput_final fs/inode.c:1571 [inline] iput+0x55d/0x900 fs/inode.c:1597 dentry_unlink_inode+0x2d9/0x400 fs/dcache.c:374 d_delete fs/dcache.c:2451 [inline] d_delete+0x128/0x160 fs/dcache.c:2440 vfs_rmdir fs/namei.c:3966 [inline] vfs_rmdir+0x41f/0x4f0 fs/namei.c:3931 do_rmdir+0x39e/0x420 fs/namei.c:4014 __do_sys_rmdir fs/namei.c:4032 [inline] __se_sys_rmdir fs/namei.c:4030 [inline] __x64_sys_rmdir+0x36/0x40 fs/namei.c:4030 do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:294 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x45b127 Code: 00 66 90 b8 57 00 00 00 0f 05 48 3d 01 f0 ff ff 0f 83 2d b9 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 b8 54 00 00 00 0f 05 <48> 3d 01 f0 ff ff 0f 83 0d b9 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007fff57350a28 EFLAGS: 00000207 ORIG_RAX: 0000000000000054 RAX: ffffffffffffffda RBX: 0000000000000065 RCX: 000000000045b127 RDX: 0000000000000000 RSI: 000000000071e698 RDI: 00007fff57351b60 RBP: 0000000000000102 R08: 0000000000000000 R09: 0000000000000001 R10: 000000000000000a R11: 0000000000000207 R12: 00007fff57351b60 R13: 0000000001773940 R14: 0000000000000000 R15: 00007fff57351b60 Allocated by task 18898: save_stack+0x23/0x90 mm/kasan/common.c:72 set_track mm/kasan/common.c:80 [inline] __kasan_kmalloc mm/kasan/common.c:515 [inline] __kasan_kmalloc.constprop.0+0xcf/0xe0 mm/kasan/common.c:488 kasan_slab_alloc+0xf/0x20 mm/kasan/common.c:523 slab_post_alloc_hook mm/slab.h:584 [inline] slab_alloc mm/slab.c:3320 [inline] kmem_cache_alloc+0x121/0x710 mm/slab.c:3484 ext4_alloc_inode+0x1f/0x5c0 fs/ext4/super.c:1119 alloc_inode+0x68/0x1e0 fs/inode.c:231 new_inode_pseudo+0x19/0xf0 fs/inode.c:927 new_inode+0x1f/0x40 fs/inode.c:956 __ext4_new_inode+0x3d5/0x4fa0 fs/ext4/ialloc.c:827 ext4_create+0x38a/0x520 fs/ext4/namei.c:2606 lookup_open+0x12d5/0x1a90 fs/namei.c:3309 do_last fs/namei.c:3401 [inline] path_openat+0xf2c/0x3490 fs/namei.c:3607 do_filp_open+0x192/0x260 fs/namei.c:3637 do_sys_openat2+0x5eb/0x7e0 fs/open.c:1149 do_sys_open+0xf2/0x180 fs/open.c:1165 __do_sys_openat fs/open.c:1179 [inline] __se_sys_openat fs/open.c:1174 [inline] __x64_sys_openat+0x9d/0x100 fs/open.c:1174 do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:294 entry_SYSCALL_64_after_hwframe+0x49/0xbe Freed by task 9: save_stack+0x23/0x90 mm/kasan/common.c:72 set_track mm/kasan/common.c:80 [inline] kasan_set_free_info mm/kasan/common.c:337 [inline] __kasan_slab_free+0x102/0x150 mm/kasan/common.c:476 kasan_slab_free+0xe/0x10 mm/kasan/common.c:485 __cache_free mm/slab.c:3426 [inline] kmem_cache_free+0x86/0x320 mm/slab.c:3694 ext4_free_in_core_inode+0x28/0x30 fs/ext4/super.c:1164 i_callback+0x44/0x80 fs/inode.c:220 rcu_do_batch kernel/rcu/tree.c:2186 [inline] rcu_core+0x5e1/0x1390 kernel/rcu/tree.c:2410 rcu_core_si+0x9/0x10 kernel/rcu/tree.c:2419 __do_softirq+0x262/0x98c kernel/softirq.c:292 The buggy address belongs to the object at ffff888096b352c0 which belongs to the cache ext4_inode_cache(49:syz2) of size 2008 The buggy address is located 912 bytes inside of 2008-byte region [ffff888096b352c0, ffff888096b35a98) The buggy address belongs to the page: page:ffffea00025acd40 refcount:1 mapcount:0 mapping:ffff8880a7474380 index:0xffff888096b35fff flags: 0xfffe0000000200(slab) raw: 00fffe0000000200 ffffea00025a66c8 ffff888091161e48 ffff8880a7474380 raw: ffff888096b35fff ffff888096b352c0 0000000100000001 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff888096b35500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888096b35580: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff888096b35600: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff888096b35680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888096b35700: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ================================================================== --- This bug is generated by a bot. 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