KASAN: slab-out-of-bounds Read in btrfs_qgroup_inherit

Status: fixed on 2024/08/06 11:02
Subsystems: btrfs
[Documentation on labels]
Reported-by: syzbot+a0d1f7e26910be4dc171@syzkaller.appspotmail.com
Fix commit: 724d8042cef8 btrfs: always do the basic checks for btrfs_qgroup_inherit structure
First crash: 781d, last: 781d
Cause bisection: introduced by (bisect log) :
commit b5357cb268c41b4e2b7383d2759fc562f5b58c33
Author: Qu Wenruo <wqu@suse.com>
Date: Sat Apr 20 07:50:27 2024 +0000

  btrfs: qgroup: do not check qgroup inherit if qgroup is disabled

Crash: KASAN: slab-out-of-bounds Read in btrfs_qgroup_inherit (log)
Repro: C syz .config
  
▶ ▼ Discussions (3)
Title Replies (including bot) Last reply
Re: [PATCH] btrfs: qgroup: fix slab-out-of-bounds in btrfs_qgroup_inherit 2 (2) 2024/06/28 01:21
[PATCH] btrfs: qgroup: fix slab-out-of-bounds in btrfs_qgroup_inherit 3 (3) 2024/06/24 05:40
[syzbot] [btrfs?] KASAN: slab-out-of-bounds Read in btrfs_qgroup_inherit 0 (1) 2024/06/08 21:42
▶ ▼ Last patch testing requests (1)
Created Duration User Patch Repo Result
2024/06/20 18:29 14m retest repro upstream error

Sample crash report:
==================================================================
BUG: KASAN: slab-out-of-bounds in btrfs_qgroup_inherit+0x42e/0x2e20 fs/btrfs/qgroup.c:3277
Read of size 8 at addr ffff88814628ca50 by task syz-executor318/5171

CPU: 0 PID: 5171 Comm: syz-executor318 Not tainted 6.10.0-rc2-syzkaller-00010-g2ab795141095 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/02/2024
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x241/0x360 lib/dump_stack.c:114
 print_address_description mm/kasan/report.c:377 [inline]
 print_report+0x169/0x550 mm/kasan/report.c:488
 kasan_report+0x143/0x180 mm/kasan/report.c:601
 btrfs_qgroup_inherit+0x42e/0x2e20 fs/btrfs/qgroup.c:3277
 create_pending_snapshot+0x1359/0x29b0 fs/btrfs/transaction.c:1854
 create_pending_snapshots+0x195/0x1d0 fs/btrfs/transaction.c:1922
 btrfs_commit_transaction+0xf20/0x3740 fs/btrfs/transaction.c:2382
 create_snapshot+0x6a1/0x9e0 fs/btrfs/ioctl.c:875
 btrfs_mksubvol+0x58f/0x710 fs/btrfs/ioctl.c:1029
 btrfs_mksnapshot+0xb5/0xf0 fs/btrfs/ioctl.c:1075
 __btrfs_ioctl_snap_create+0x387/0x4b0 fs/btrfs/ioctl.c:1340
 btrfs_ioctl_snap_create_v2+0x1f2/0x3a0 fs/btrfs/ioctl.c:1422
 btrfs_ioctl+0x99e/0xc60
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:907 [inline]
 __se_sys_ioctl+0xfc/0x170 fs/ioctl.c:893
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fcbf1992509
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 81 18 00 00 90 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 b0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fcbf1928218 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007fcbf1a1f618 RCX: 00007fcbf1992509
RDX: 0000000020000280 RSI: 0000000050009417 RDI: 0000000000000003
RBP: 00007fcbf1a1f610 R08: 00007ffea1298e97 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007fcbf19eb660
R13: 00000000200002b8 R14: 00007fcbf19e60c0 R15: 0030656c69662f2e
 </TASK>

Allocated by task 5171:
 kasan_save_stack mm/kasan/common.c:47 [inline]
 kasan_save_track+0x3f/0x80 mm/kasan/common.c:68
 poison_kmalloc_redzone mm/kasan/common.c:370 [inline]
 __kasan_kmalloc+0x98/0xb0 mm/kasan/common.c:387
 kasan_kmalloc include/linux/kasan.h:211 [inline]
 __do_kmalloc_node mm/slub.c:4121 [inline]
 kmalloc_node_track_caller_noprof+0x225/0x440 mm/slub.c:4141
 memdup_user+0x2b/0xc0 mm/util.c:214
 btrfs_ioctl_snap_create_v2+0x2fd/0x3a0 fs/btrfs/ioctl.c:1411
 btrfs_ioctl+0x99e/0xc60
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:907 [inline]
 __se_sys_ioctl+0xfc/0x170 fs/ioctl.c:893
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

The buggy address belongs to the object at ffff88814628ca00
 which belongs to the cache kmalloc-96 of size 96
The buggy address is located 0 bytes to the right of
 allocated 80-byte region [ffff88814628ca00, ffff88814628ca50)

The buggy address belongs to the physical page:
page: refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x14628c
flags: 0x57ff00000000000(node=1|zone=2|lastcpupid=0x7ff)
page_type: 0xffffefff(slab)
raw: 057ff00000000000 ffff888015041280 dead000000000100 dead000000000122
raw: 0000000000000000 0000000080200020 00000001ffffefff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 0, migratetype Unmovable, gfp_mask 0x252800(GFP_NOWAIT|__GFP_NORETRY|__GFP_COMP|__GFP_THISNODE), pid 1, tgid 1 (swapper/0), ts 7530129564, free_ts 7138110092
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x1f3/0x230 mm/page_alloc.c:1468
 prep_new_page mm/page_alloc.c:1476 [inline]
 get_page_from_freelist+0x2e2d/0x2ee0 mm/page_alloc.c:3402
 __alloc_pages_noprof+0x256/0x6c0 mm/page_alloc.c:4660
 __alloc_pages_node_noprof include/linux/gfp.h:269 [inline]
 alloc_pages_node_noprof include/linux/gfp.h:296 [inline]
 alloc_slab_page+0x5f/0x120 mm/slub.c:2264
 allocate_slab+0x5a/0x2e0 mm/slub.c:2427
 new_slab mm/slub.c:2480 [inline]
 ___slab_alloc+0xcd1/0x14b0 mm/slub.c:3666
 __slab_alloc+0x58/0xa0 mm/slub.c:3756
 __slab_alloc_node mm/slub.c:3809 [inline]
 slab_alloc_node mm/slub.c:3988 [inline]
 kmalloc_node_trace_noprof+0x20c/0x300 mm/slub.c:4160
 kmalloc_node_noprof include/linux/slab.h:677 [inline]
 alloc_node_nr_active kernel/workqueue.c:4833 [inline]
 alloc_workqueue+0x847/0x2060 kernel/workqueue.c:5713
 nvmet_init+0x8d/0x150 drivers/nvme/target/core.c:1698
 do_one_initcall+0x248/0x880 init/main.c:1267
 do_initcall_level+0x157/0x210 init/main.c:1329
 do_initcalls+0x3f/0x80 init/main.c:1345
 kernel_init_freeable+0x435/0x5d0 init/main.c:1578
 kernel_init+0x1d/0x2b0 init/main.c:1467
 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147
page last free pid 1 tgid 1 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 free_pages_prepare mm/page_alloc.c:1088 [inline]
 free_unref_page+0xd19/0xea0 mm/page_alloc.c:2565
 vfree+0x186/0x2e0 mm/vmalloc.c:3346
 free_partitions block/partitions/core.c:110 [inline]
 check_partition block/partitions/core.c:169 [inline]
 blk_add_partitions block/partitions/core.c:579 [inline]
 bdev_disk_changed+0x80e/0x13d0 block/partitions/core.c:683
 blkdev_get_whole+0x315/0x470 block/bdev.c:700
 bdev_open+0x2e9/0xc60 block/bdev.c:909
 bdev_file_open_by_dev+0x1b0/0x230 block/bdev.c:1011
 disk_scan_partitions+0x1be/0x2b0 block/genhd.c:367
 device_add_disk+0xca0/0xf90 block/genhd.c:510
 add_disk include/linux/blkdev.h:715 [inline]
 brd_alloc+0x503/0x770 drivers/block/brd.c:373
 brd_init+0xfd/0x1d0 drivers/block/brd.c:435
 do_one_initcall+0x248/0x880 init/main.c:1267
 do_initcall_level+0x157/0x210 init/main.c:1329
 do_initcalls+0x3f/0x80 init/main.c:1345
 kernel_init_freeable+0x435/0x5d0 init/main.c:1578
 kernel_init+0x1d/0x2b0 init/main.c:1467
 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147

Memory state around the buggy address:
 ffff88814628c900: fa fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc
 ffff88814628c980: fa fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc
>ffff88814628ca00: 00 00 00 00 00 00 00 00 00 00 fc fc fc fc fc fc
                                                 ^
 ffff88814628ca80: fa fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc
 ffff88814628cb00: 00 00 00 00 00 00 00 00 00 00 fc fc fc fc fc fc
==================================================================

Crashes (2):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2024/06/04 22:29 upstream 2ab795141095 11f2afa5 .config strace log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro] ci2-upstream-fs KASAN: slab-out-of-bounds Read in btrfs_qgroup_inherit
2024/06/04 21:35 upstream 2ab795141095 11f2afa5 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs KASAN: slab-out-of-bounds Read in btrfs_qgroup_inherit
* Struck through repros no longer work on HEAD.