syzbot

 sign-in | mailing list | source | docs
🐞 Open [1596]
≡ Subsystems
🐞 Fixed [6224]
🐞 Invalid [15742]
⬇ Missing Backports [183]
≡ Crashes
Kernel Health Bugs/Month Bug Lifetimes Fuzzing
Total Repo Heatmap Subsystems Heatmap
💬 Send us feedback

KASAN: use-after-free Read in bch2_check_dirents

Status: upstream: reported C repro on 2024/11/15 11:11
Subsystems: bcachefs
[Documentation on labels]
Reported-by: syzbot+fea0322882c0cba65f11@syzkaller.appspotmail.com
First crash: 178d, last: 3d00h
Cause bisection: introduced by (bisect log) :
commit d97de0d017cde0d442c3d144b4f969f43064cc0f
Author: Kent Overstreet <kent.overstreet@linux.dev>
Date: Tue Aug 13 01:31:25 2024 +0000

  bcachefs: Make bkey_fsck_err() a wrapper around fsck_err()

Crash: kernel BUG in vfs_get_tree (log)
Repro: C syz .config
  
▶ ▼ Discussions (1)
Title Replies (including bot) Last reply
[syzbot] [bcachefs?] KASAN: use-after-free Read in bch2_check_dirents 0 (2) 2024/12/05 20:34
▶ ▼ Last patch testing requests (1)
Created Duration User Patch Repo Result
2024/11/29 04:50 18m retest repro upstream report log
▶ ▼ Cause bisection attempts (2)
Created Duration User Patch Repo Result
2024/12/05 12:29 8h04m bisect upstream OK (1) job log log
2024/11/15 04:47 11h03m bisect upstream OK (1) job log log
marked invalid by nogikh@google.com

Sample crash report:
bcachefs (loop0): check_inodes... done
bcachefs (loop0): check_extents... done
bcachefs (loop0): check_dirents...
dirent points to missing inode:
u64s 8 type dirent 4096:6728544935518790663:U32_MAX len 0 ver 0: lost+found -> 4097 type dir, fixing
==================================================================
BUG: KASAN: use-after-free in check_dirent fs/bcachefs/fsck.c:2443 [inline]
BUG: KASAN: use-after-free in bch2_check_dirents+0x2b68/0x3e90 fs/bcachefs/fsck.c:2468
Read of size 1 at addr ffff88805d564048 by task syz-executor265/6269

CPU: 1 UID: 0 PID: 6269 Comm: syz-executor265 Not tainted 6.14.0-rc3-syzkaller-00166-g334426094588 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 12/27/2024
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120
 print_address_description mm/kasan/report.c:408 [inline]
 print_report+0x16e/0x5b0 mm/kasan/report.c:521
 kasan_report+0x143/0x180 mm/kasan/report.c:634
 check_dirent fs/bcachefs/fsck.c:2443 [inline]
 bch2_check_dirents+0x2b68/0x3e90 fs/bcachefs/fsck.c:2468
 bch2_run_recovery_pass+0xf0/0x1e0 fs/bcachefs/recovery_passes.c:226
 bch2_run_recovery_passes+0x2ad/0xa90 fs/bcachefs/recovery_passes.c:291
 bch2_fs_recovery+0x2c48/0x3de0 fs/bcachefs/recovery.c:973
 bch2_fs_start+0x37c/0x610 fs/bcachefs/super.c:1041
 bch2_fs_get_tree+0xdb7/0x17a0 fs/bcachefs/fs.c:2203
 vfs_get_tree+0x90/0x2b0 fs/super.c:1814
 do_new_mount+0x2be/0xb40 fs/namespace.c:3560
 do_mount fs/namespace.c:3900 [inline]
 __do_sys_mount fs/namespace.c:4111 [inline]
 __se_sys_mount+0x2d6/0x3c0 fs/namespace.c:4088
 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: 0033:0x7eff7d61461a
Code: d8 64 89 02 48 c7 c0 ff ff ff ff eb a6 e8 5e 04 00 00 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 49 89 ca b8 a5 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffd68e9c008 EFLAGS: 00000282 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007eff7d61461a
RDX: 0000400000000000 RSI: 0000400000000040 RDI: 00007ffd68e9c050
RBP: 0000000000000004 R08: 00007ffd68e9c090 R09: 0000000000005956
R10: 0000000001000001 R11: 0000000000000282 R12: 0000000001000000
R13: 00007ffd68e9c090 R14: 0000400000000000 R15: 0000000000000003
 </TASK>

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x5d564
flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000000000 0000000000000000 dead000000000122 0000000000000000
raw: 0000000000000000 0000000000000000 00000000ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as freed
page last allocated via order 5, migratetype Unmovable, gfp_mask 0x52800(GFP_NOWAIT|__GFP_NORETRY|__GFP_COMP), pid 6269, tgid 6269 (syz-executor265), ts 106334437847, free_ts 106682597280
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x1f4/0x240 mm/page_alloc.c:1551
 prep_new_page mm/page_alloc.c:1559 [inline]
 get_page_from_freelist+0x3651/0x37a0 mm/page_alloc.c:3477
 __alloc_frozen_pages_noprof+0x292/0x710 mm/page_alloc.c:4739
 __alloc_pages_noprof+0xa/0x30 mm/page_alloc.c:4773
 __alloc_pages_node_noprof include/linux/gfp.h:265 [inline]
 alloc_pages_node_noprof include/linux/gfp.h:292 [inline]
 ___kmalloc_large_node+0x8b/0x1d0 mm/slub.c:4239
 __kmalloc_large_node_noprof+0x1a/0x80 mm/slub.c:4266
 __do_kmalloc_node mm/slub.c:4282 [inline]
 __kmalloc_node_noprof+0x33a/0x4d0 mm/slub.c:4300
 __kvmalloc_node_noprof+0x72/0x190 mm/util.c:662
 btree_bounce_alloc fs/bcachefs/btree_io.c:123 [inline]
 btree_node_sort+0x620/0x1830 fs/bcachefs/btree_io.c:322
 bch2_btree_post_write_cleanup+0x11a/0xa70 fs/bcachefs/btree_io.c:2293
 bch2_btree_node_prep_for_write+0x345/0x660 fs/bcachefs/btree_trans_commit.c:93
 bch2_trans_lock_write+0x68e/0xc60 fs/bcachefs/btree_trans_commit.c:129
 do_bch2_trans_commit fs/bcachefs/btree_trans_commit.c:862 [inline]
 __bch2_trans_commit+0x258c/0x9790 fs/bcachefs/btree_trans_commit.c:1070
 __bch2_str_hash_check_key+0x1ea4/0x3ac0
 bch2_str_hash_check_key fs/bcachefs/str_hash.h:415 [inline]
 check_dirent fs/bcachefs/fsck.c:2373 [inline]
 bch2_check_dirents+0x2eb0/0x3e90 fs/bcachefs/fsck.c:2468
 bch2_run_recovery_pass+0xf0/0x1e0 fs/bcachefs/recovery_passes.c:226
page last free pid 6269 tgid 6269 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 free_pages_prepare mm/page_alloc.c:1127 [inline]
 __free_pages_ok+0xbbc/0xe40 mm/page_alloc.c:1271
 __folio_put+0x2b3/0x360 mm/swap.c:112
 folio_put include/linux/mm.h:1489 [inline]
 free_large_kmalloc+0xfe/0x180 mm/slub.c:4728
 kfree+0x212/0x430 mm/slub.c:4751
 btree_bounce_free fs/bcachefs/btree_io.c:111 [inline]
 btree_node_sort+0x1100/0x1830 fs/bcachefs/btree_io.c:379
 bch2_btree_post_write_cleanup+0x11a/0xa70 fs/bcachefs/btree_io.c:2293
 bch2_btree_node_prep_for_write+0x345/0x660 fs/bcachefs/btree_trans_commit.c:93
 bch2_trans_lock_write+0x68e/0xc60 fs/bcachefs/btree_trans_commit.c:129
 do_bch2_trans_commit fs/bcachefs/btree_trans_commit.c:862 [inline]
 __bch2_trans_commit+0x258c/0x9790 fs/bcachefs/btree_trans_commit.c:1070
 bch2_trans_commit fs/bcachefs/btree_update.h:183 [inline]
 check_dirent fs/bcachefs/fsck.c:2438 [inline]
 bch2_check_dirents+0x28be/0x3e90 fs/bcachefs/fsck.c:2468
 bch2_run_recovery_pass+0xf0/0x1e0 fs/bcachefs/recovery_passes.c:226
 bch2_run_recovery_passes+0x2ad/0xa90 fs/bcachefs/recovery_passes.c:291
 bch2_fs_recovery+0x2c48/0x3de0 fs/bcachefs/recovery.c:973
 bch2_fs_start+0x37c/0x610 fs/bcachefs/super.c:1041
 bch2_fs_get_tree+0xdb7/0x17a0 fs/bcachefs/fs.c:2203
 vfs_get_tree+0x90/0x2b0 fs/super.c:1814

Memory state around the buggy address:
 ffff88805d563f00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff88805d563f80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
>ffff88805d564000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                                              ^
 ffff88805d564080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff88805d564100: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
==================================================================

Crashes (139):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/02/21 13:25 upstream 334426094588 0808a665 .config strace log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro] ci2-upstream-fs KASAN: use-after-free Read in bch2_check_dirents
2024/11/15 04:43 upstream cfaaa7d010d1 a8c99394 .config console log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro] ci2-upstream-fs KASAN: use-after-free Read in bch2_check_dirents
2025/02/15 03:49 linux-next 0ae0fa3bf0b4 40a34ec9 .config console log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro] ci-upstream-linux-next-kasan-gce-root KASAN: use-after-free Read in bch2_check_dirents
2025/04/26 12:49 upstream f1a3944c860b c6b4fb39 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs KASAN: use-after-free Read in bch2_check_dirents
2025/04/22 14:56 upstream a33b5a08cbbd 2a20f901 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs KASAN: use-after-free Read in bch2_check_dirents
2025/04/19 03:11 upstream 3088d26962e8 2a20f901 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs KASAN: use-after-free Read in bch2_check_dirents
2025/04/07 16:46 upstream 0af2f6be1b42 a2ada0e7 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root KASAN: use-after-free Read in bch2_check_dirents
2025/04/03 17:30 upstream a1b5bd45d4ee 996a9618 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs KASAN: use-after-free Read in bch2_check_dirents
2025/04/02 02:30 upstream 08733088b566 d863cf4b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root KASAN: use-after-free Read in bch2_check_dirents
2025/04/01 10:35 upstream 609706855d90 36d76a97 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root KASAN: use-after-free Read in bch2_check_dirents
2025/03/30 00:01 upstream 7d06015d936c d3999433 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root KASAN: use-after-free Read in bch2_check_dirents
2025/03/29 09:23 upstream eff5f16bfd87 cf25e2c2 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root KASAN: use-after-free Read in bch2_check_dirents
2025/03/24 19:40 upstream 38fec10eb60d 875573af .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs KASAN: use-after-free Read in bch2_check_dirents
2025/03/22 07:10 upstream d07de43e3f05 c6512ef7 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs KASAN: use-after-free Read in bch2_check_dirents
2025/05/09 09:22 upstream 9c69f8884904 3af71fd3 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root KASAN: use-after-free Read in bch2_check_dirents
2025/05/08 15:57 upstream d76bb1ebb558 dbf35fa1 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root KASAN: use-after-free Read in bch2_check_dirents
2025/05/07 17:58 upstream 707df3375124 dbf35fa1 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root KASAN: use-after-free Read in bch2_check_dirents
2025/05/07 13:34 upstream 0d8d44db295c 350f4ffc .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root KASAN: use-after-free Read in bch2_check_dirents
2025/05/06 04:43 upstream 01f95500a162 ae98e6b9 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root KASAN: use-after-free Read in bch2_check_dirents
2025/05/02 17:53 upstream ebd297a2affa d7f099d1 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root KASAN: use-after-free Read in bch2_check_dirents
2025/04/29 03:19 upstream f15d97df5afa aeb6ec69 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root KASAN: use-after-free Read in bch2_check_dirents
2025/04/27 23:12 upstream b4432656b36e c6b4fb39 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root KASAN: use-after-free Read in bch2_check_dirents
2025/04/27 08:00 upstream 5bc1018675ec c6b4fb39 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root KASAN: use-after-free Read in bch2_check_dirents
2025/04/27 05:05 upstream 5bc1018675ec c6b4fb39 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root KASAN: use-after-free Read in bch2_check_dirents
2025/04/27 03:37 upstream 5bc1018675ec c6b4fb39 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root KASAN: use-after-free Read in bch2_check_dirents
2025/04/25 18:48 upstream 02ddfb981de8 dea5c7e4 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root KASAN: use-after-free Read in bch2_check_dirents
2025/04/25 11:37 upstream 02ddfb981de8 dea5c7e4 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root KASAN: use-after-free Read in bch2_check_dirents
2025/04/24 15:31 upstream a79be02bba5c 9c80ffa0 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root KASAN: use-after-free Read in bch2_check_dirents
2025/04/24 05:26 upstream a79be02bba5c 9882047a .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root KASAN: use-after-free Read in bch2_check_dirents
2025/04/22 19:28 upstream a33b5a08cbbd 53a8b9bd .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root KASAN: use-after-free Read in bch2_check_dirents
2025/04/22 11:27 upstream a33b5a08cbbd 2a20f901 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root KASAN: use-after-free Read in bch2_check_dirents
2025/04/21 20:00 upstream 9d7a0577c9db 2a20f901 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root KASAN: use-after-free Read in bch2_check_dirents
2025/04/20 05:01 upstream 119009db2674 2a20f901 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root KASAN: use-after-free Read in bch2_check_dirents
2025/04/20 00:22 upstream 8560697b23dc 2a20f901 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root KASAN: use-after-free Read in bch2_check_dirents
2025/04/15 16:58 upstream 1a1d569a75f3 85125322 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root KASAN: use-after-free Read in bch2_check_dirents
2025/04/15 15:26 upstream 834a4a689699 85125322 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root KASAN: use-after-free Read in bch2_check_dirents
2025/04/14 13:37 upstream 8ffd015db85f 0bd6db41 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root KASAN: use-after-free Read in bch2_check_dirents
2025/04/13 00:46 upstream 3bde70a2c827 0bd6db41 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root KASAN: use-after-free Read in bch2_check_dirents
2025/04/11 17:42 upstream 900241a5cc15 12ba9c21 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root KASAN: use-after-free Read in bch2_check_dirents
2025/04/11 13:26 upstream 900241a5cc15 12ba9c21 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root KASAN: use-after-free Read in bch2_check_dirents
2025/04/10 05:26 upstream 3b07108ada81 988b336c .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root KASAN: use-after-free Read in bch2_check_dirents
2025/04/09 23:57 upstream 3b07108ada81 988b336c .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root KASAN: use-after-free Read in bch2_check_dirents
2025/04/09 20:57 upstream a24588245776 47d015b1 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root KASAN: use-after-free Read in bch2_check_dirents
2025/04/08 08:54 upstream 0af2f6be1b42 a2ada0e7 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root KASAN: use-after-free Read in bch2_check_dirents
2025/04/08 05:45 upstream 0af2f6be1b42 a2ada0e7 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root KASAN: use-after-free Read in bch2_check_dirents
2025/04/08 03:32 upstream 0af2f6be1b42 a2ada0e7 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root KASAN: use-after-free Read in bch2_check_dirents
2025/04/07 14:44 upstream 0af2f6be1b42 2f0c9720 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root KASAN: use-after-free Read in bch2_check_dirents
2025/04/07 11:13 upstream 0af2f6be1b42 2f0c9720 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root KASAN: use-after-free Read in bch2_check_dirents
2025/04/05 00:27 upstream e48e99b6edf4 c53ea9c9 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root KASAN: use-after-free Read in bch2_check_dirents
2025/04/04 23:13 upstream e48e99b6edf4 c53ea9c9 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root KASAN: use-after-free Read in bch2_check_dirents
2025/04/04 06:13 upstream 06a22366d6a1 1740c707 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root KASAN: use-after-free Read in bch2_check_dirents
2025/04/03 16:01 upstream a2cc6ff5ec8f d7ae3a11 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root KASAN: use-after-free Read in bch2_check_dirents
2025/03/28 06:57 upstream 4fa118e5b79f 6c09fb82 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root KASAN: use-after-free Read in bch2_check_dirents
2025/03/23 16:21 upstream 586de92313fc 4e8d3850 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root KASAN: use-after-free Read in bch2_check_dirents
2025/03/22 22:35 upstream 183601b78a9b c6512ef7 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root KASAN: use-after-free Read in bch2_check_dirents
2025/04/12 01:40 linux-next 01c6df60d5d4 12ba9c21 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root KASAN: use-after-free Read in bch2_check_dirents
2025/03/02 21:13 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci e056da87c780 c3901742 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 KASAN: use-after-free Read in bch2_check_dirents
* Struck through repros no longer work on HEAD.