================================================================== BUG: KASAN: use-after-free in btrfs_printk+0x38b/0x40c fs/btrfs/super.c:246 Read of size 8 at addr ffff88806e0186a8 by task syz-executor.4/19819 CPU: 0 PID: 19819 Comm: syz-executor.4 Not tainted 5.9.0-rc8-next-20201007-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+0x198/0x1fb lib/dump_stack.c:118 print_address_description.constprop.0.cold+0xae/0x497 mm/kasan/report.c:385 __kasan_report mm/kasan/report.c:545 [inline] kasan_report.cold+0x1f/0x37 mm/kasan/report.c:562 btrfs_printk+0x38b/0x40c fs/btrfs/super.c:246 device_list_add.cold+0x99/0x31e fs/btrfs/volumes.c:943 btrfs_scan_one_device+0x339/0x4a0 fs/btrfs/volumes.c:1360 btrfs_mount_root+0x4d5/0xbb0 fs/btrfs/super.c:1633 legacy_get_tree+0x105/0x220 fs/fs_context.c:592 vfs_get_tree+0x89/0x2f0 fs/super.c:1549 fc_mount fs/namespace.c:983 [inline] vfs_kern_mount.part.0+0xd3/0x170 fs/namespace.c:1013 vfs_kern_mount+0x3c/0x60 fs/namespace.c:1000 btrfs_mount+0x234/0xa60 fs/btrfs/super.c:1731 legacy_get_tree+0x105/0x220 fs/fs_context.c:592 vfs_get_tree+0x89/0x2f0 fs/super.c:1549 do_new_mount fs/namespace.c:2896 [inline] path_mount+0x12ae/0x1e70 fs/namespace.c:3227 __do_sys_mount fs/namespace.c:3438 [inline] __se_sys_mount fs/namespace.c:3411 [inline] __x64_sys_mount+0x278/0x2f0 fs/namespace.c:3411 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x46087a Code: b8 a6 00 00 00 0f 05 48 3d 01 f0 ff ff 0f 83 ad 89 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 49 89 ca b8 a5 00 00 00 0f 05 <48> 3d 01 f0 ff ff 0f 83 8a 89 fb ff c3 66 0f 1f 84 00 00 00 00 00 RSP: 002b:00007f789777aa88 EFLAGS: 00000202 ORIG_RAX: 00000000000000a5 RAX: ffffffffffffffda RBX: 00007f789777ab20 RCX: 000000000046087a RDX: 0000000020000000 RSI: 0000000020000100 RDI: 00007f789777aae0 RBP: 00007f789777aae0 R08: 00007f789777ab20 R09: 0000000020000000 R10: 0000000000000000 R11: 0000000000000202 R12: 0000000020000000 R13: 0000000020000100 R14: 0000000020000200 R15: 000000002001ec00 Allocated by task 19773: kasan_save_stack+0x1b/0x40 mm/kasan/common.c:48 kasan_set_track mm/kasan/common.c:56 [inline] __kasan_kmalloc.constprop.0+0xbf/0xd0 mm/kasan/common.c:461 kmalloc_node include/linux/slab.h:577 [inline] kvmalloc_node+0xb4/0xf0 mm/util.c:575 kvmalloc include/linux/mm.h:765 [inline] kvzalloc include/linux/mm.h:773 [inline] btrfs_mount_root+0x117/0xbb0 fs/btrfs/super.c:1612 legacy_get_tree+0x105/0x220 fs/fs_context.c:592 vfs_get_tree+0x89/0x2f0 fs/super.c:1549 fc_mount fs/namespace.c:983 [inline] vfs_kern_mount.part.0+0xd3/0x170 fs/namespace.c:1013 vfs_kern_mount+0x3c/0x60 fs/namespace.c:1000 btrfs_mount+0x234/0xa60 fs/btrfs/super.c:1731 legacy_get_tree+0x105/0x220 fs/fs_context.c:592 vfs_get_tree+0x89/0x2f0 fs/super.c:1549 do_new_mount fs/namespace.c:2896 [inline] path_mount+0x12ae/0x1e70 fs/namespace.c:3227 __do_sys_mount fs/namespace.c:3438 [inline] __se_sys_mount fs/namespace.c:3411 [inline] __x64_sys_mount+0x278/0x2f0 fs/namespace.c:3411 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xa9 Freed by task 19773: kasan_save_stack+0x1b/0x40 mm/kasan/common.c:48 kasan_set_track+0x1c/0x30 mm/kasan/common.c:56 kasan_set_free_info+0x1b/0x30 mm/kasan/generic.c:355 __kasan_slab_free+0xd8/0x120 mm/kasan/common.c:422 __cache_free mm/slab.c:3420 [inline] kfree+0x10e/0x2a0 mm/slab.c:3758 kvfree+0x42/0x50 mm/util.c:604 deactivate_locked_super+0x94/0x160 fs/super.c:335 btrfs_mount_root+0x772/0xbb0 fs/btrfs/super.c:1677 legacy_get_tree+0x105/0x220 fs/fs_context.c:592 vfs_get_tree+0x89/0x2f0 fs/super.c:1549 fc_mount fs/namespace.c:983 [inline] vfs_kern_mount.part.0+0xd3/0x170 fs/namespace.c:1013 vfs_kern_mount+0x3c/0x60 fs/namespace.c:1000 btrfs_mount+0x234/0xa60 fs/btrfs/super.c:1731 legacy_get_tree+0x105/0x220 fs/fs_context.c:592 vfs_get_tree+0x89/0x2f0 fs/super.c:1549 do_new_mount fs/namespace.c:2896 [inline] path_mount+0x12ae/0x1e70 fs/namespace.c:3227 __do_sys_mount fs/namespace.c:3438 [inline] __se_sys_mount fs/namespace.c:3411 [inline] __x64_sys_mount+0x278/0x2f0 fs/namespace.c:3411 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xa9 The buggy address belongs to the object at ffff88806e018000 which belongs to the cache kmalloc-16k of size 16384 The buggy address is located 1704 bytes inside of 16384-byte region [ffff88806e018000, ffff88806e01c000) The buggy address belongs to the page: page:0000000065d725ae refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x6e018 head:0000000065d725ae order:3 compound_mapcount:0 compound_pincount:0 flags: 0xfffe0000010200(slab|head) raw: 00fffe0000010200 ffffea0001d9dc08 ffffea0001c18808 ffff88800ec40b00 raw: 0000000000000000 ffff88806e018000 0000000100000001 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff88806e018580: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88806e018600: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff88806e018680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff88806e018700: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88806e018780: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================