Message-ID: <6759a9b9.050a0220.1ac542.000d.GAE@google.com>
Date: Wed, 11 Dec 2024 07:03:21 -0800
From: syzbot <syzbot+8517da8635307182c8a5@...kaller.appspotmail.com>
To: clm@...com, dsterba@...e.com, josef@...icpanda.com, 
	linux-btrfs@...r.kernel.org, linux-kernel@...r.kernel.org, 
	syzkaller-bugs@...glegroups.com
Subject: [syzbot] [btrfs?] KASAN: slab-use-after-free Read in btrfs_cow_block

Hello,

syzbot found the following issue on:

HEAD commit:    b5f217084ab3 Merge tag 'bpf-fixes' of git://git.kernel.org..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=1055f020580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=1362a5aee630ff34
dashboard link: https://syzkaller.appspot.com/bug?extid=8517da8635307182c8a5
compiler:       Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/7feb34a89c2a/non_bootable_disk-b5f21708.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/858a023f110b/vmlinux-b5f21708.xz
kernel image: https://storage.googleapis.com/syzbot-assets/4b03d6afaab4/bzImage-b5f21708.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+8517da8635307182c8a5@...kaller.appspotmail.com

loop0: detected capacity change from 0 to 32768
BTRFS: device fsid ed167579-eb65-4e76-9a50-61ac97e9b59d devid 1 transid 8 /dev/loop0 (7:0) scanned by syz.0.0 (5315)
BTRFS info (device loop0): first mount of filesystem ed167579-eb65-4e76-9a50-61ac97e9b59d
BTRFS info (device loop0): using sha256 (sha256-avx2) checksum algorithm
BTRFS info (device loop0): rebuilding free space tree
BTRFS info (device loop0): disabling free space tree
BTRFS info (device loop0): clearing compat-ro feature flag for FREE_SPACE_TREE (0x1)
BTRFS info (device loop0): clearing compat-ro feature flag for FREE_SPACE_TREE_VALID (0x2)
BTRFS info (device loop0): balance: start -d -m
BTRFS info (device loop0): relocating block group 6881280 flags data|metadata
BTRFS info (device loop0): relocating block group 5242880 flags data|metadata
==================================================================
BUG: KASAN: slab-use-after-free in do_perf_trace_btrfs_cow_block include/trace/events/btrfs.h:1082 [inline]
BUG: KASAN: slab-use-after-free in perf_trace_btrfs_cow_block+0x398/0x780 include/trace/events/btrfs.h:1082
Read of size 8 at addr ffff888011f09000 by task syz.0.0/5315

CPU: 0 UID: 0 PID: 5315 Comm: syz.0.0 Not tainted 6.13.0-rc1-syzkaller-00316-gb5f217084ab3 #0
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014
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:378 [inline]
 print_report+0x169/0x550 mm/kasan/report.c:489
 kasan_report+0x143/0x180 mm/kasan/report.c:602
 do_perf_trace_btrfs_cow_block include/trace/events/btrfs.h:1082 [inline]
 perf_trace_btrfs_cow_block+0x398/0x780 include/trace/events/btrfs.h:1082
 trace_btrfs_cow_block include/trace/events/btrfs.h:1082 [inline]
 btrfs_cow_block+0x9d9/0xa40 fs/btrfs/ctree.c:757
 btrfs_search_slot+0xc01/0x3180 fs/btrfs/ctree.c:2156
 btrfs_update_root+0xf6/0xc70 fs/btrfs/root-tree.c:144
 commit_fs_roots+0x4cd/0x720 fs/btrfs/transaction.c:1509
 btrfs_commit_transaction+0xfa7/0x3720 fs/btrfs/transaction.c:2428
 relocate_block_group+0xc09/0xd40 fs/btrfs/relocation.c:3760
 btrfs_relocate_block_group+0x77d/0xd90 fs/btrfs/relocation.c:4081
 btrfs_relocate_chunk+0x12c/0x3b0 fs/btrfs/volumes.c:3494
 __btrfs_balance+0x1b0f/0x26b0 fs/btrfs/volumes.c:4278
 btrfs_balance+0xbdc/0x10c0 fs/btrfs/volumes.c:4655
 btrfs_ioctl_balance+0x493/0x7c0 fs/btrfs/ioctl.c:3670
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:906 [inline]
 __se_sys_ioctl+0xf5/0x170 fs/ioctl.c:892
 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: 0033:0x7fc4b797fed9
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 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 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fc4b8866058 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007fc4b7b45fa0 RCX: 00007fc4b797fed9
RDX: 0000000020000180 RSI: 00000000c4009420 RDI: 0000000000000006
RBP: 00007fc4b79f3cc8 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007fc4b7b45fa0 R15: 00007ffc798d71d8
 </TASK>

Allocated by task 5315:
 kasan_save_stack mm/kasan/common.c:47 [inline]
 kasan_save_track+0x3f/0x80 mm/kasan/common.c:68
 unpoison_slab_object mm/kasan/common.c:319 [inline]
 __kasan_slab_alloc+0x66/0x80 mm/kasan/common.c:345
 kasan_slab_alloc include/linux/kasan.h:250 [inline]
 slab_post_alloc_hook mm/slub.c:4104 [inline]
 slab_alloc_node mm/slub.c:4153 [inline]
 kmem_cache_alloc_noprof+0x1d9/0x380 mm/slub.c:4160
 __alloc_extent_buffer+0x33/0x170 fs/btrfs/extent_io.c:2617
 alloc_extent_buffer+0x1ad/0x2740 fs/btrfs/extent_io.c:3019
 btrfs_init_new_buffer fs/btrfs/extent-tree.c:5019 [inline]
 btrfs_alloc_tree_block+0x28e/0x1440 fs/btrfs/extent-tree.c:5132
 btrfs_force_cow_block+0x526/0x1da0 fs/btrfs/ctree.c:573
 btrfs_cow_block+0x35e/0xa40 fs/btrfs/ctree.c:754
 btrfs_search_slot+0xc01/0x3180 fs/btrfs/ctree.c:2156
 btrfs_insert_empty_items fs/btrfs/ctree.c:4354 [inline]
 btrfs_insert_empty_item fs/btrfs/ctree.h:669 [inline]
 btrfs_insert_item+0x1a0/0x3b0 fs/btrfs/ctree.c:4383
 create_reloc_root+0x60f/0x9a0 fs/btrfs/relocation.c:741
 btrfs_init_reloc_root+0x338/0x4f0 fs/btrfs/relocation.c:817
 record_root_in_trans+0x2c9/0x360 fs/btrfs/transaction.c:450
 btrfs_record_root_in_trans+0x164/0x190 fs/btrfs/transaction.c:496
 select_reloc_root+0x27e/0xfd0 fs/btrfs/relocation.c:2101
 do_relocation+0x329/0x1a50 fs/btrfs/relocation.c:2326
 relocate_tree_block fs/btrfs/relocation.c:2658 [inline]
 relocate_tree_blocks+0xf34/0x1dd0 fs/btrfs/relocation.c:2712
 relocate_block_group+0x755/0xd40 fs/btrfs/relocation.c:3680
 btrfs_relocate_block_group+0x77d/0xd90 fs/btrfs/relocation.c:4081
 btrfs_relocate_chunk+0x12c/0x3b0 fs/btrfs/volumes.c:3494
 __btrfs_balance+0x1b0f/0x26b0 fs/btrfs/volumes.c:4278
 btrfs_balance+0xbdc/0x10c0 fs/btrfs/volumes.c:4655
 btrfs_ioctl_balance+0x493/0x7c0 fs/btrfs/ioctl.c:3670
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:906 [inline]
 __se_sys_ioctl+0xf5/0x170 fs/ioctl.c:892
 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

Freed by task 8:
 kasan_save_stack mm/kasan/common.c:47 [inline]
 kasan_save_track+0x3f/0x80 mm/kasan/common.c:68
 kasan_save_free_info+0x40/0x50 mm/kasan/generic.c:582
 poison_slab_object mm/kasan/common.c:247 [inline]
 __kasan_slab_free+0x59/0x70 mm/kasan/common.c:264
 kasan_slab_free include/linux/kasan.h:233 [inline]
 slab_free_hook mm/slub.c:2338 [inline]
 slab_free mm/slub.c:4598 [inline]
 kmem_cache_free+0x195/0x410 mm/slub.c:4700
 rcu_do_batch kernel/rcu/tree.c:2567 [inline]
 rcu_core+0xaaa/0x17a0 kernel/rcu/tree.c:2823
 handle_softirqs+0x2d4/0x9b0 kernel/softirq.c:554
 do_softirq+0x11b/0x1e0 kernel/softirq.c:455
 __local_bh_enable_ip+0x1bb/0x200 kernel/softirq.c:382
 ipv6_get_lladdr+0x295/0x3d0 net/ipv6/addrconf.c:1936
 mld_newpack+0x337/0xaf0 net/ipv6/mcast.c:1755
 add_grhead net/ipv6/mcast.c:1850 [inline]
 add_grec+0x1492/0x19a0 net/ipv6/mcast.c:1988
 mld_send_initial_cr+0x228/0x4b0 net/ipv6/mcast.c:2234
 mld_dad_work+0x44/0x500 net/ipv6/mcast.c:2260
 process_one_work kernel/workqueue.c:3229 [inline]
 process_scheduled_works+0xa66/0x1840 kernel/workqueue.c:3310
 worker_thread+0x870/0xd30 kernel/workqueue.c:3391
 kthread+0x2f0/0x390 kernel/kthread.c:389
 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244

Last potentially related work creation:
 kasan_save_stack+0x3f/0x60 mm/kasan/common.c:47
 __kasan_record_aux_stack+0xac/0xc0 mm/kasan/generic.c:544
 __call_rcu_common kernel/rcu/tree.c:3086 [inline]
 call_rcu+0x167/0xa70 kernel/rcu/tree.c:3190
 release_extent_buffer+0x206/0x2c0 fs/btrfs/extent_io.c:3230
 btrfs_force_cow_block+0xf9c/0x1da0 fs/btrfs/ctree.c:659
 btrfs_cow_block+0x35e/0xa40 fs/btrfs/ctree.c:754
 btrfs_search_slot+0xc01/0x3180 fs/btrfs/ctree.c:2156
 btrfs_update_root+0xf6/0xc70 fs/btrfs/root-tree.c:144
 commit_fs_roots+0x4cd/0x720 fs/btrfs/transaction.c:1509
 btrfs_commit_transaction+0xfa7/0x3720 fs/btrfs/transaction.c:2428
 relocate_block_group+0xc09/0xd40 fs/btrfs/relocation.c:3760
 btrfs_relocate_block_group+0x77d/0xd90 fs/btrfs/relocation.c:4081
 btrfs_relocate_chunk+0x12c/0x3b0 fs/btrfs/volumes.c:3494
 __btrfs_balance+0x1b0f/0x26b0 fs/btrfs/volumes.c:4278
 btrfs_balance+0xbdc/0x10c0 fs/btrfs/volumes.c:4655
 btrfs_ioctl_balance+0x493/0x7c0 fs/btrfs/ioctl.c:3670
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:906 [inline]
 __se_sys_ioctl+0xf5/0x170 fs/ioctl.c:892
 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 ffff888011f09000
 which belongs to the cache btrfs_extent_buffer of size 416
The buggy address is located 0 bytes inside of
 freed 416-byte region [ffff888011f09000, ffff888011f091a0)

The buggy address belongs to the physical page:
page: refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x11f09
flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 00fff00000000000 ffff88803fe35640 dead000000000122 0000000000000000
raw: 0000000000000000 0000000000080008 00000001f5000000 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 0x52c40(GFP_NOFS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP), pid 5315, tgid 5314 (syz.0.0), ts 76027898168, free_ts 75595688995
 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+0x365c/0x37a0 mm/page_alloc.c:3474
 __alloc_pages_noprof+0x292/0x710 mm/page_alloc.c:4751
 alloc_pages_mpol_noprof+0x3e8/0x680 mm/mempolicy.c:2265
 alloc_slab_page+0x6a/0x140 mm/slub.c:2408
 allocate_slab+0x5a/0x2f0 mm/slub.c:2574
 new_slab mm/slub.c:2627 [inline]
 ___slab_alloc+0xcd1/0x14b0 mm/slub.c:3815
 __slab_alloc+0x58/0xa0 mm/slub.c:3905
 __slab_alloc_node mm/slub.c:3980 [inline]
 slab_alloc_node mm/slub.c:4141 [inline]
 kmem_cache_alloc_noprof+0x268/0x380 mm/slub.c:4160
 __alloc_extent_buffer+0x33/0x170 fs/btrfs/extent_io.c:2617
 alloc_extent_buffer+0x1ad/0x2740 fs/btrfs/extent_io.c:3019
 btrfs_init_new_buffer fs/btrfs/extent-tree.c:5019 [inline]
 btrfs_alloc_tree_block+0x28e/0x1440 fs/btrfs/extent-tree.c:5132
 btrfs_force_cow_block+0x526/0x1da0 fs/btrfs/ctree.c:573
 btrfs_cow_block+0x35e/0xa40 fs/btrfs/ctree.c:754
 btrfs_search_slot+0xc01/0x3180 fs/btrfs/ctree.c:2156
 btrfs_insert_empty_items fs/btrfs/ctree.c:4354 [inline]
 btrfs_insert_empty_item fs/btrfs/ctree.h:669 [inline]
 btrfs_insert_item+0x1a0/0x3b0 fs/btrfs/ctree.c:4383
page last free pid 4722 tgid 4722 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 free_pages_prepare mm/page_alloc.c:1127 [inline]
 free_unref_page+0xdef/0x1130 mm/page_alloc.c:2657
 __slab_free+0x31b/0x3d0 mm/slub.c:4509
 qlink_free mm/kasan/quarantine.c:163 [inline]
 qlist_free_all+0x9a/0x140 mm/kasan/quarantine.c:179
 kasan_quarantine_reduce+0x14f/0x170 mm/kasan/quarantine.c:286
 __kasan_slab_alloc+0x23/0x80 mm/kasan/common.c:329
 kasan_slab_alloc include/linux/kasan.h:250 [inline]
 slab_post_alloc_hook mm/slub.c:4104 [inline]
 slab_alloc_node mm/slub.c:4153 [inline]
 kmem_cache_alloc_noprof+0x1d9/0x380 mm/slub.c:4160
 getname_flags+0xb7/0x540 fs/namei.c:139
 do_readlinkat+0xd8/0x3a0 fs/stat.c:561
 __do_sys_readlink fs/stat.c:599 [inline]
 __se_sys_readlink fs/stat.c:596 [inline]
 __x64_sys_readlink+0x7f/0x90 fs/stat.c:596
 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

Memory state around the buggy address:
 ffff888011f08f00: 00 00 00 00 00 00 fc fc fc fc 00 00 00 00 00 00
 ffff888011f08f80: 00 00 00 00 fc fc fc fc fc fc fc fc fc fc fc fc
>ffff888011f09000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                   ^
 ffff888011f09080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff888011f09100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================


---
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