syzbot


KASAN: slab-use-after-free Read in bch2_sb_errors_from_cpu

Status: fixed on 2024/07/09 19:14
Subsystems: bcachefs
[Documentation on labels]
Reported-by: syzbot+a2bc0e838efd7663f4d9@syzkaller.appspotmail.com
Fix commit: 211c581de28e bcachefs: slab-use-after-free Read in bch2_sb_errors_from_cpu
First crash: 32d, last: 32d
Discussions (2)
Title Replies (including bot) Last reply
[PATCH] bcachefs: slab-use-after-free Read in bch2_sb_errors_from_cpu 2 (2) 2024/06/25 21:52
[syzbot] [bcachefs?] KASAN: slab-use-after-free Read in bch2_sb_errors_from_cpu 0 (3) 2024/06/25 19:31
Last patch testing requests (2)
Created Duration User Patch Repo Result
2024/06/25 19:31 22m peili.dev@gmail.com patch upstream OK log
2024/06/25 19:13 12m peili.dev@gmail.com patch upstream error

Sample crash report:
==================================================================
BUG: KASAN: slab-use-after-free in bch2_sb_errors_from_cpu+0x255/0x280 fs/bcachefs/sb-errors.c:122
Read of size 8 at addr ffff88801ac73100 by task kworker/u32:2/45

CPU: 3 PID: 45 Comm: kworker/u32:2 Not tainted 6.10.0-rc4-syzkaller-00164-g66cc544fd75c #0
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
Workqueue: btree_update btree_interior_update_work
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:114
 print_address_description mm/kasan/report.c:377 [inline]
 print_report+0xc3/0x620 mm/kasan/report.c:488
 kasan_report+0xd9/0x110 mm/kasan/report.c:601
 bch2_sb_errors_from_cpu+0x255/0x280 fs/bcachefs/sb-errors.c:122
 bch2_write_super+0x12b2/0x37a0 fs/bcachefs/super-io.c:969
 btree_update_new_nodes_mark_sb fs/bcachefs/btree_update_interior.c:626 [inline]
 btree_update_nodes_written fs/bcachefs/btree_update_interior.c:688 [inline]
 btree_interior_update_work+0x46e/0x2cb0 fs/bcachefs/btree_update_interior.c:859
 process_one_work+0x9fb/0x1b60 kernel/workqueue.c:3231
 process_scheduled_works kernel/workqueue.c:3312 [inline]
 worker_thread+0x6c8/0xf70 kernel/workqueue.c:3393
 kthread+0x2c1/0x3a0 kernel/kthread.c:389
 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
 </TASK>

Allocated by task 5596:
 kasan_save_stack+0x33/0x60 mm/kasan/common.c:47
 kasan_save_track+0x14/0x30 mm/kasan/common.c:68
 poison_kmalloc_redzone mm/kasan/common.c:370 [inline]
 __kasan_kmalloc+0xaa/0xb0 mm/kasan/common.c:387
 kasan_kmalloc include/linux/kasan.h:211 [inline]
 __do_kmalloc_node mm/slub.c:4122 [inline]
 __kmalloc_node_noprof+0x215/0x440 mm/slub.c:4129
 kmalloc_node_noprof include/linux/slab.h:681 [inline]
 kvmalloc_node_noprof+0x9d/0x1a0 mm/util.c:634
 kvmalloc_array_node_noprof include/linux/slab.h:800 [inline]
 __bch2_darray_resize+0xd8/0x250 fs/bcachefs/darray.c:12
 __darray_resize fs/bcachefs/darray.h:31 [inline]
 __darray_make_room fs/bcachefs/darray.h:43 [inline]
 bch2_sb_error_count+0x34f/0x4e0 fs/bcachefs/sb-errors.c:102
 __bch2_inode_invalid+0x2c6/0x4d0 fs/bcachefs/inode.c:441
 bch2_inode_v3_invalid+0x1f1/0x2e0 fs/bcachefs/inode.c:529
 bch2_bkey_val_invalid+0x222/0x2f0 fs/bcachefs/bkey_methods.c:143
 bch2_btree_node_read_done+0x3294/0x4fe0 fs/bcachefs/btree_io.c:1232
 btree_node_read_work+0x567/0x1060 fs/bcachefs/btree_io.c:1345
 bch2_btree_node_read+0x8b3/0xe40 fs/bcachefs/btree_io.c:1730
 __bch2_btree_root_read fs/bcachefs/btree_io.c:1769 [inline]
 bch2_btree_root_read+0x2ca/0x690 fs/bcachefs/btree_io.c:1793
 read_btree_roots fs/bcachefs/recovery.c:475 [inline]
 bch2_fs_recovery+0x1ba8/0x3db0 fs/bcachefs/recovery.c:803
 bch2_fs_start+0x2e9/0x600 fs/bcachefs/super.c:1035
 bch2_fs_open+0xfa0/0x1110 fs/bcachefs/super.c:2127
 bch2_mount+0xe2c/0x1230 fs/bcachefs/fs.c:1919
 legacy_get_tree+0x109/0x220 fs/fs_context.c:662
 vfs_get_tree+0x8f/0x380 fs/super.c:1780
 do_new_mount fs/namespace.c:3352 [inline]
 path_mount+0x14e6/0x1f20 fs/namespace.c:3679
 do_mount fs/namespace.c:3692 [inline]
 __do_sys_mount fs/namespace.c:3898 [inline]
 __se_sys_mount fs/namespace.c:3875 [inline]
 __x64_sys_mount+0x297/0x320 fs/namespace.c:3875
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Freed by task 5596:
 kasan_save_stack+0x33/0x60 mm/kasan/common.c:47
 kasan_save_track+0x14/0x30 mm/kasan/common.c:68
 kasan_save_free_info+0x3b/0x60 mm/kasan/generic.c:579
 poison_slab_object+0xf7/0x160 mm/kasan/common.c:240
 __kasan_slab_free+0x32/0x50 mm/kasan/common.c:256
 kasan_slab_free include/linux/kasan.h:184 [inline]
 slab_free_hook mm/slub.c:2196 [inline]
 slab_free mm/slub.c:4437 [inline]
 kfree+0x12a/0x3b0 mm/slub.c:4558
 kvfree+0x47/0x50 mm/util.c:680
 __bch2_darray_resize+0x185/0x250 fs/bcachefs/darray.c:18
 __darray_resize fs/bcachefs/darray.h:31 [inline]
 __darray_make_room fs/bcachefs/darray.h:43 [inline]
 bch2_sb_error_count+0x34f/0x4e0 fs/bcachefs/sb-errors.c:102
 bch2_fsck_err+0x180/0x1730 fs/bcachefs/error.c:210
 bch2_bucket_ref_update+0xcd3/0xf80 fs/bcachefs/buckets.c:834
 __mark_pointer+0x10c/0x410 fs/bcachefs/buckets.c:1000
 bch2_trigger_pointer.constprop.0+0xce4/0x25c0 fs/bcachefs/buckets.c:1037
 __trigger_extent+0x414/0xc00 fs/bcachefs/buckets.c:1176
 bch2_trigger_extent+0x4ee/0x5d0 fs/bcachefs/buckets.c:1261
 bch2_key_trigger fs/bcachefs/bkey_methods.h:88 [inline]
 bch2_key_trigger_new fs/bcachefs/bkey_methods.h:116 [inline]
 run_one_trans_trigger fs/bcachefs/btree_trans_commit.c:517 [inline]
 run_btree_triggers+0x6f1/0xd10 fs/bcachefs/btree_trans_commit.c:544
 bch2_trans_commit_run_triggers fs/bcachefs/btree_trans_commit.c:576 [inline]
 __bch2_trans_commit+0x366/0x7ad0 fs/bcachefs/btree_trans_commit.c:1022
 bch2_trans_commit fs/bcachefs/btree_update.h:170 [inline]
 bch2_extent_update+0x494/0xa40 fs/bcachefs/io_write.c:326
 bch2_fpunch_at+0x7e6/0xbc0 fs/bcachefs/io_misc.c:184
 __bch2_resume_logged_op_truncate+0x4ce/0x7a0 fs/bcachefs/io_misc.c:260
 bch2_truncate+0x1e1/0x220 fs/bcachefs/io_misc.c:291
 bchfs_truncate+0x90c/0xd70 fs/bcachefs/fs-io.c:476
 bch2_setattr+0x1ab/0x250 fs/bcachefs/fs.c:918
 notify_change+0x742/0x11f0 fs/attr.c:497
 do_truncate+0x15c/0x220 fs/open.c:65
 vfs_truncate+0x3ef/0x4e0 fs/open.c:111
 do_sys_truncate fs/open.c:134 [inline]
 __do_sys_truncate fs/open.c:146 [inline]
 __se_sys_truncate fs/open.c:144 [inline]
 __x64_sys_truncate+0x177/0x1f0 fs/open.c:144
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

The buggy address belongs to the object at ffff88801ac73100
 which belongs to the cache kmalloc-16 of size 16
The buggy address is located 0 bytes inside of
 freed 16-byte region [ffff88801ac73100, ffff88801ac73110)

The buggy address belongs to the physical page:
page: refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x1ac73
flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff)
page_type: 0xffffefff(slab)
raw: 00fff00000000000 ffff888015442640 ffffea0000675400 dead000000000002
raw: 0000000000000000 0000000000800080 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 0xd2820(GFP_ATOMIC|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 1, tgid 1 (init), ts 23767929677, free_ts 22379130869
 create_dummy_stack mm/page_owner.c:94 [inline]
 register_dummy_stack+0x8a/0xd0 mm/page_owner.c:100
 init_page_owner+0x48/0xbf0 mm/page_owner.c:118
 invoke_init_callbacks mm/page_ext.c:148 [inline]
 page_ext_init+0x6af/0xaa0 mm/page_ext.c:493
 mm_core_init+0x68d/0x740 mm/mm_init.c:2725
page last free pid 8 tgid 8 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 free_pages_prepare mm/page_alloc.c:1088 [inline]
 free_unref_page+0x64a/0xe40 mm/page_alloc.c:2583
 vfree+0x181/0x7a0 mm/vmalloc.c:3346
 delayed_vfree_work+0x56/0x70 mm/vmalloc.c:3267
 process_one_work+0x9fb/0x1b60 kernel/workqueue.c:3231
 process_scheduled_works kernel/workqueue.c:3312 [inline]
 worker_thread+0x6c8/0xf70 kernel/workqueue.c:3393
 kthread+0x2c1/0x3a0 kernel/kthread.c:389
 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244

Memory state around the buggy address:
 ffff88801ac73000: 00 00 fc fc fa fb fc fc fa fb fc fc fa fb fc fc
 ffff88801ac73080: fa fb fc fc fa fb fc fc fa fb fc fc fa fb fc fc
>ffff88801ac73100: fa fb fc fc fa fb fc fc fa fb fc fc fa fb fc fc
                   ^
 ffff88801ac73180: fa fb fc fc fa fb fc fc fa fb fc fc fa fb fc fc
 ffff88801ac73200: fa fb fc fc fa fb fc fc fa fb fc fc fa fb fc fc
==================================================================

Crashes (2):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2024/06/22 05:57 upstream 66cc544fd75c c2e07261 .config console log report syz / log C [disk image (non-bootable)] [vmlinux] [kernel image] [mounted in repro] ci-qemu-upstream KASAN: slab-use-after-free Read in bch2_sb_errors_from_cpu
2024/06/22 03:30 upstream 66cc544fd75c c2e07261 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream KASAN: slab-use-after-free Read in bch2_sb_errors_from_cpu
* Struck through repros no longer work on HEAD.