Message-ID: <67447b3c.050a0220.1cc393.0084.GAE@google.com>
Date: Mon, 25 Nov 2024 05:27:24 -0800
From: syzbot <syzbot+92e65e9b7a42d379f92e@...kaller.appspotmail.com>
To: bfoster@...hat.com, kent.overstreet@...ux.dev, 
	linux-bcachefs@...r.kernel.org, linux-kernel@...r.kernel.org, 
	syzkaller-bugs@...glegroups.com
Subject: [syzbot] [bcachefs?] KASAN: use-after-free Read in bch2_btree_node_read_done

Hello,

syzbot found the following issue on:

HEAD commit:    228a1157fb9f Merge tag '6.13-rc-part1-SMB3-client-fixes' o..
git tree:       upstream
console+strace: https://syzkaller.appspot.com/x/log.txt?x=16300530580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=402159daa216c89d
dashboard link: https://syzkaller.appspot.com/bug?extid=92e65e9b7a42d379f92e
compiler:       Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=159bfb78580000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=170169c0580000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/d32a8e8c5aae/disk-228a1157.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/28d5c070092e/vmlinux-228a1157.xz
kernel image: https://storage.googleapis.com/syzbot-assets/45af4bfd9e8e/bzImage-228a1157.xz
mounted in repro: https://storage.googleapis.com/syzbot-assets/4b641b27822f/mount_0.gz

The issue was bisected to:

commit 03ef80b469d5d83530ce1ce15be78a40e5300f9b
Author: Kent Overstreet <kent.overstreet@...ux.dev>
Date:   Sat Sep 23 22:41:51 2023 +0000

    bcachefs: Ignore unknown mount options

bisection log:  https://syzkaller.appspot.com/x/bisect.txt?x=11388778580000
final oops:     https://syzkaller.appspot.com/x/report.txt?x=13388778580000
console output: https://syzkaller.appspot.com/x/log.txt?x=15388778580000

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+92e65e9b7a42d379f92e@...kaller.appspotmail.com
Fixes: 03ef80b469d5 ("bcachefs: Ignore unknown mount options")

  node offset 8/24 bset u64s 375 bset byte offset 184: keys out of order: u64s 11 type alloc_v4 0:32:0 len 0 ver 0 > u64s 11 type alloc_v4 0:2:0 len 0 ver 0, fixing
bcachefs (loop0): btree_node_read_work: rewriting btree node at btree=alloc level=0 SPOS_MAX due to error
==================================================================
BUG: KASAN: use-after-free in bch2_btree_node_read_done+0xfbe/0x5e90 fs/bcachefs/btree_io.c:1087
Read of size 8 at addr ffff888076abc010 by task syz-executor345/5842

CPU: 1 UID: 0 PID: 5842 Comm: syz-executor345 Not tainted 6.12.0-syzkaller-08446-g228a1157fb9f #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
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:377 [inline]
 print_report+0x169/0x550 mm/kasan/report.c:488
 kasan_report+0x143/0x180 mm/kasan/report.c:601
 bch2_btree_node_read_done+0xfbe/0x5e90 fs/bcachefs/btree_io.c:1087
 btree_node_read_work+0x68b/0x1260 fs/bcachefs/btree_io.c:1323
 bch2_btree_node_read+0x2433/0x2a10
 __bch2_btree_root_read fs/bcachefs/btree_io.c:1749 [inline]
 bch2_btree_root_read+0x617/0x7a0 fs/bcachefs/btree_io.c:1771
 read_btree_roots+0x296/0x840 fs/bcachefs/recovery.c:523
 bch2_fs_recovery+0x2585/0x39d0 fs/bcachefs/recovery.c:853
 bch2_fs_start+0x356/0x5b0 fs/bcachefs/super.c:1037
 bch2_fs_get_tree+0xd68/0x1710 fs/bcachefs/fs.c:2170
 vfs_get_tree+0x90/0x2b0 fs/super.c:1814
 do_new_mount+0x2be/0xb40 fs/namespace.c:3507
 do_mount fs/namespace.c:3847 [inline]
 __do_sys_mount fs/namespace.c:4057 [inline]
 __se_sys_mount+0x2d6/0x3c0 fs/namespace.c:4034
 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: 0033:0x7fc4572667ea
Code: d8 64 89 02 48 c7 c0 ff ff ff ff eb a6 e8 3e 06 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:00007ffd22484098 EFLAGS: 00000282 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fc4572667ea
RDX: 00000000200000c0 RSI: 0000000020000180 RDI: 00007ffd224840f0
RBP: 0000000000000004 R08: 00007ffd22484130 R09: 000000000000593e
R10: 0000000000000010 R11: 0000000000000282 R12: 00007ffd22484130
R13: 0000000001000000 R14: 0000000000000003 R15: 0000000000000010
 </TASK>

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x76abc
flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000000000 ffffea0001ca0108 ffff8880b87447e0 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 2, migratetype Reclaimable, gfp_mask 0x452cd0(GFP_KERNEL_ACCOUNT|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_RECLAIMABLE), pid 5842, tgid 5842 (syz-executor345), ts 64163821991, free_ts 64389007908
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x1f3/0x230 mm/page_alloc.c:1556
 prep_new_page mm/page_alloc.c:1564 [inline]
 get_page_from_freelist+0x363e/0x3790 mm/page_alloc.c:3474
 __alloc_pages_noprof+0x292/0x710 mm/page_alloc.c:4751
 __alloc_pages_node_noprof include/linux/gfp.h:269 [inline]
 alloc_pages_node_noprof include/linux/gfp.h:296 [inline]
 ___kmalloc_large_node+0x8b/0x1d0 mm/slub.c:4209
 __kmalloc_large_node_noprof+0x1a/0x80 mm/slub.c:4236
 __do_kmalloc_node mm/slub.c:4252 [inline]
 __kmalloc_node_noprof+0x2d2/0x440 mm/slub.c:4270
 __kvmalloc_node_noprof+0x72/0x190 mm/util.c:658
 btree_node_data_alloc+0xdb/0x260 fs/bcachefs/btree_cache.c:153
 __bch2_btree_node_mem_alloc+0x1d8/0x3e0 fs/bcachefs/btree_cache.c:198
 bch2_fs_btree_cache_init+0x26f/0x630 fs/bcachefs/btree_cache.c:653
 bch2_fs_alloc fs/bcachefs/super.c:917 [inline]
 bch2_fs_open+0x2aa4/0x2f80 fs/bcachefs/super.c:2065
 bch2_fs_get_tree+0x738/0x1710 fs/bcachefs/fs.c:2157
 vfs_get_tree+0x90/0x2b0 fs/super.c:1814
 do_new_mount+0x2be/0xb40 fs/namespace.c:3507
 do_mount fs/namespace.c:3847 [inline]
 __do_sys_mount fs/namespace.c:4057 [inline]
 __se_sys_mount+0x2d6/0x3c0 fs/namespace.c:4034
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
page last free pid 5842 tgid 5842 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 free_pages_prepare mm/page_alloc.c:1127 [inline]
 free_unref_page+0xded/0x1130 mm/page_alloc.c:2657
 __folio_put+0x2c7/0x440 mm/swap.c:112
 folio_put include/linux/mm.h:1490 [inline]
 free_large_kmalloc+0x105/0x1c0 mm/slub.c:4698
 kfree+0x21c/0x440 mm/slub.c:4721
 btree_bounce_free fs/bcachefs/btree_io.c:112 [inline]
 bch2_btree_node_read_done+0x3c8a/0x5e90 fs/bcachefs/btree_io.c:1209
 btree_node_read_work+0x68b/0x1260 fs/bcachefs/btree_io.c:1323
 bch2_btree_node_read+0x2433/0x2a10
 __bch2_btree_root_read fs/bcachefs/btree_io.c:1749 [inline]
 bch2_btree_root_read+0x617/0x7a0 fs/bcachefs/btree_io.c:1771
 read_btree_roots+0x296/0x840 fs/bcachefs/recovery.c:523
 bch2_fs_recovery+0x2585/0x39d0 fs/bcachefs/recovery.c:853
 bch2_fs_start+0x356/0x5b0 fs/bcachefs/super.c:1037
 bch2_fs_get_tree+0xd68/0x1710 fs/bcachefs/fs.c:2170
 vfs_get_tree+0x90/0x2b0 fs/super.c:1814
 do_new_mount+0x2be/0xb40 fs/namespace.c:3507
 do_mount fs/namespace.c:3847 [inline]
 __do_sys_mount fs/namespace.c:4057 [inline]
 __se_sys_mount+0x2d6/0x3c0 fs/namespace.c:4034
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83

Memory state around the buggy address:
 ffff888076abbf00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff888076abbf80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff888076abc000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                         ^
 ffff888076abc080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff888076abc100: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
==================================================================


---
This report is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
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For information about bisection process see: https://goo.gl/tpsmEJ#bisection

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