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Date:   Thu, 03 Mar 2022 02:35:19 -0800
Message-ID: <00000000000066b78e05d94df48b@google.com>
Subject: [syzbot] KASAN: use-after-free Read in btrfs_scan_one_device (2)
From:   syzbot <syzbot+82650a4e0ed38f218363@syzkaller.appspotmail.com>
To:     clm@fb.com, dsterba@suse.com, josef@toxicpanda.com,
        linux-btrfs@vger.kernel.org, linux-kernel@vger.kernel.org,
        syzkaller-bugs@googlegroups.com, terrelln@fb.com
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Hello,

syzbot found the following issue on:

HEAD commit:    2293be58d6a1 Merge tag 'trace-v5.17-rc4' of git://git.kern..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=15f8b2d4700000
kernel config:  https://syzkaller.appspot.com/x/.config?x=5f28851401b410e5
dashboard link: https://syzkaller.appspot.com/bug?extid=82650a4e0ed38f218363
compiler:       gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=152ee696700000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=11739502700000

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+82650a4e0ed38f218363@syzkaller.appspotmail.com

==================================================================
BUG: KASAN: use-after-free in btrfs_printk+0x395/0x425 fs/btrfs/super.c:244
Read of size 8 at addr ffff8880237906d8 by task udevd/3694

CPU: 1 PID: 3694 Comm: udevd Not tainted 5.17.0-rc5-syzkaller-00306-g2293be58d6a1 #0
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.14.0-2 04/01/2014
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106
 print_address_description.constprop.0.cold+0x8d/0x303 mm/kasan/report.c:255
 __kasan_report mm/kasan/report.c:442 [inline]
 kasan_report.cold+0x83/0xdf mm/kasan/report.c:459
 btrfs_printk+0x395/0x425 fs/btrfs/super.c:244
 device_list_add.cold+0xd7/0x2ed fs/btrfs/volumes.c:957
 btrfs_scan_one_device+0x4c7/0x5c0 fs/btrfs/volumes.c:1387
 btrfs_control_ioctl+0x12a/0x2d0 fs/btrfs/super.c:2409
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:874 [inline]
 __se_sys_ioctl fs/ioctl.c:860 [inline]
 __x64_sys_ioctl+0x193/0x200 fs/ioctl.c:860
 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: 0033:0x7f86e0e090e7
Code: 3c 1c e8 1c ff ff ff 85 c0 79 87 49 c7 c4 ff ff ff ff 5b 5d 4c 89 e0 41 5c c3 66 0f 1f 84 00 00 00 00 00 b8 10 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d 61 9d 0c 00 f7 d8 64 89 01 48
RSP: 002b:00007ffcb6ec2788 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f86e0e090e7
RDX: 00007ffcb6ec2798 RSI: 0000000090009427 RDI: 0000000000000009
RBP: 0000000000000009 R08: 000055f3f60246f0 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ffcb6ec37d8 R14: 000055f3f7c4fbc0 R15: 00007f86e0cac6c0
 </TASK>

Allocated by task 3672:
 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_kmalloc mm/kasan/common.c:515 [inline]
 ____kasan_kmalloc mm/kasan/common.c:474 [inline]
 __kasan_kmalloc+0xa6/0xd0 mm/kasan/common.c:524
 kmalloc_node include/linux/slab.h:604 [inline]
 kvmalloc_node+0x97/0x100 mm/util.c:580
 kvmalloc include/linux/slab.h:731 [inline]
 kvzalloc include/linux/slab.h:739 [inline]
 btrfs_mount_root+0x118/0xc10 fs/btrfs/super.c:1665
 legacy_get_tree+0x105/0x220 fs/fs_context.c:610
 vfs_get_tree+0x89/0x2f0 fs/super.c:1497
 fc_mount fs/namespace.c:1030 [inline]
 vfs_kern_mount.part.0+0xd3/0x170 fs/namespace.c:1060
 vfs_kern_mount+0x3c/0x60 fs/namespace.c:1047
 btrfs_mount+0x234/0xa60 fs/btrfs/super.c:1784
 legacy_get_tree+0x105/0x220 fs/fs_context.c:610
 vfs_get_tree+0x89/0x2f0 fs/super.c:1497
 do_new_mount fs/namespace.c:3024 [inline]
 path_mount+0x1320/0x1fa0 fs/namespace.c:3354
 do_mount fs/namespace.c:3367 [inline]
 __do_sys_mount fs/namespace.c:3575 [inline]
 __se_sys_mount fs/namespace.c:3552 [inline]
 __x64_sys_mount+0x27f/0x300 fs/namespace.c:3552
 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

Freed by task 3672:
 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+0xff/0x140 mm/kasan/common.c:328
 kasan_slab_free include/linux/kasan.h:236 [inline]
 __cache_free mm/slab.c:3437 [inline]
 kfree+0xf8/0x2b0 mm/slab.c:3794
 kvfree+0x42/0x50 mm/util.c:613
 deactivate_locked_super+0x94/0x160 fs/super.c:332
 btrfs_mount_root+0x78e/0xc10 fs/btrfs/super.c:1730
 legacy_get_tree+0x105/0x220 fs/fs_context.c:610
 vfs_get_tree+0x89/0x2f0 fs/super.c:1497
 fc_mount fs/namespace.c:1030 [inline]
 vfs_kern_mount.part.0+0xd3/0x170 fs/namespace.c:1060
 vfs_kern_mount+0x3c/0x60 fs/namespace.c:1047
 btrfs_mount+0x234/0xa60 fs/btrfs/super.c:1784
 legacy_get_tree+0x105/0x220 fs/fs_context.c:610
 vfs_get_tree+0x89/0x2f0 fs/super.c:1497
 do_new_mount fs/namespace.c:3024 [inline]
 path_mount+0x1320/0x1fa0 fs/namespace.c:3354
 do_mount fs/namespace.c:3367 [inline]
 __do_sys_mount fs/namespace.c:3575 [inline]
 __se_sys_mount fs/namespace.c:3552 [inline]
 __x64_sys_mount+0x27f/0x300 fs/namespace.c:3552
 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

The buggy address belongs to the object at ffff888023790000
 which belongs to the cache kmalloc-16k of size 16384
The buggy address is located 1752 bytes inside of
 16384-byte region [ffff888023790000, ffff888023794000)
The buggy address belongs to the page:
page:ffffea00008de400 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x23790
head:ffffea00008de400 order:3 compound_mapcount:0 compound_pincount:0
flags: 0xfff00000010200(slab|head|node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000010200 ffffea0000990008 ffffea000098fe08 ffff888010c40b00
raw: 0000000000000000 ffff888023790000 0000000100000001 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 0x2520c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_THISNODE), pid 3672, ts 53936584194, free_ts 53419420055
 prep_new_page mm/page_alloc.c:2434 [inline]
 get_page_from_freelist+0xa72/0x2f50 mm/page_alloc.c:4165
 __alloc_pages+0x1b2/0x500 mm/page_alloc.c:5389
 __alloc_pages_node include/linux/gfp.h:572 [inline]
 kmem_getpages mm/slab.c:1378 [inline]
 cache_grow_begin+0x75/0x390 mm/slab.c:2584
 cache_alloc_refill+0x27f/0x380 mm/slab.c:2957
 ____cache_alloc mm/slab.c:3040 [inline]
 ____cache_alloc mm/slab.c:3023 [inline]
 slab_alloc_node mm/slab.c:3241 [inline]
 kmem_cache_alloc_node_trace+0x49c/0x5b0 mm/slab.c:3609
 __do_kmalloc_node mm/slab.c:3631 [inline]
 __kmalloc_node+0x38/0x60 mm/slab.c:3639
 kmalloc_node include/linux/slab.h:604 [inline]
 kvmalloc_node+0x97/0x100 mm/util.c:580
 kvmalloc include/linux/slab.h:731 [inline]
 kvzalloc include/linux/slab.h:739 [inline]
 btrfs_mount_root+0x118/0xc10 fs/btrfs/super.c:1665
 legacy_get_tree+0x105/0x220 fs/fs_context.c:610
 vfs_get_tree+0x89/0x2f0 fs/super.c:1497
 fc_mount fs/namespace.c:1030 [inline]
 vfs_kern_mount.part.0+0xd3/0x170 fs/namespace.c:1060
 vfs_kern_mount+0x3c/0x60 fs/namespace.c:1047
 btrfs_mount+0x234/0xa60 fs/btrfs/super.c:1784
 legacy_get_tree+0x105/0x220 fs/fs_context.c:610
 vfs_get_tree+0x89/0x2f0 fs/super.c:1497
 do_new_mount fs/namespace.c:3024 [inline]
 path_mount+0x1320/0x1fa0 fs/namespace.c:3354
page last free stack trace:
 reset_page_owner include/linux/page_owner.h:24 [inline]
 free_pages_prepare mm/page_alloc.c:1352 [inline]
 free_pcp_prepare+0x374/0x870 mm/page_alloc.c:1404
 free_unref_page_prepare mm/page_alloc.c:3325 [inline]
 free_unref_page+0x19/0x690 mm/page_alloc.c:3404
 __put_page+0x193/0x1e0 mm/swap.c:128
 folio_put include/linux/mm.h:1199 [inline]
 put_page include/linux/mm.h:1237 [inline]
 do_exit+0x1f5f/0x2a30 kernel/exit.c:845
 do_group_exit+0xd2/0x2f0 kernel/exit.c:935
 __do_sys_exit_group kernel/exit.c:946 [inline]
 __se_sys_exit_group kernel/exit.c:944 [inline]
 __x64_sys_exit_group+0x3a/0x50 kernel/exit.c:944
 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:
 ffff888023790580: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff888023790600: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff888023790680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                                    ^
 ffff888023790700: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff888023790780: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================


---
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