[syzbot] [f2fs?] KASAN: slab-use-after-free Read in f2fs_filemap_fault

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 052d534373b7 Merge tag 'exfat-for-6.8-rc1' of git://git.ke..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=14bb9913e80000
kernel config: https://syzkaller.appspot.com/x/.config?x=490fc2f9d4ae426c
dashboard link: https://syzkaller.appspot.com/bug?extid=763afad57075d3f862f2
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=15d9fbcbe80000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=1422d5ebe80000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/51de89c7a81e/disk-052d5343.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/7e03b92536a3/vmlinux-052d5343.xz
kernel image: https://storage.googleapis.com/syzbot-assets/3d91124eb5ff/bzImage-052d5343.xz
mounted in repro #1: https://storage.googleapis.com/syzbot-assets/f67519526788/mount_0.gz
mounted in repro #2: https://storage.googleapis.com/syzbot-assets/7e871268c842/mount_7.gz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+763afa...@syzkaller.appspotmail.com

==================================================================
BUG: KASAN: slab-use-after-free in f2fs_filemap_fault+0xd1/0x2c0 fs/f2fs/file.c:49
Read of size 8 at addr ffff88807bb22680 by task syz-executor184/5058

CPU: 0 PID: 5058 Comm: syz-executor184 Not tainted 6.7.0-syzkaller-09928-g052d534373b7 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/17/2023
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0x1e7/0x2d0 lib/dump_stack.c:106
print_address_description mm/kasan/report.c:377 [inline]
print_report+0x163/0x540 mm/kasan/report.c:488
kasan_report+0x142/0x170 mm/kasan/report.c:601
f2fs_filemap_fault+0xd1/0x2c0 fs/f2fs/file.c:49
__do_fault+0x131/0x450 mm/memory.c:4376
do_shared_fault mm/memory.c:4798 [inline]
do_fault mm/memory.c:4872 [inline]
do_pte_missing mm/memory.c:3745 [inline]
handle_pte_fault mm/memory.c:5144 [inline]
__handle_mm_fault+0x23b7/0x72b0 mm/memory.c:5285
handle_mm_fault+0x27e/0x770 mm/memory.c:5450
do_user_addr_fault arch/x86/mm/fault.c:1364 [inline]
handle_page_fault arch/x86/mm/fault.c:1507 [inline]
exc_page_fault+0x456/0x870 arch/x86/mm/fault.c:1563
asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:570
RIP: 0033:0x7f808e742b50
Code: 20 bf 02 00 00 00 e8 9f 24 04 00 48 83 f8 ff 0f 84 08 fa ff ff 48 89 05 e6 65 0c 00 e9 fc f9 ff ff 66 0f 1f 84 00 00 00 00 00 <c7> 04 25 40 00 00 20 66 32 66 73 c6 04 25 44 00 00 20 00 e9 0f fa
RSP: 002b:00007f808e735170 EFLAGS: 00010246

RAX: 0000000000000000 RBX: 00007f808e80b6e8 RCX: 00007f808e784fe9
RDX: 86d0f56bab720225 RSI: 0000000000000000 RDI: 00007f808e7355a0
RBP: 00007f808e80b6e0 R08: 0000000000000000 R09: 00007f808e7356c0
R10: 00007f808e80b6e0 R11: 0000000000000246 R12: 00007f808e80b6ec
R13: 0000000000000000 R14: 00007fff41e6fc30 R15: 00007fff41e6fd18
</TASK>

Allocated by task 5058:
kasan_save_stack mm/kasan/common.c:47 [inline]
kasan_save_track+0x3f/0x70 mm/kasan/common.c:68
unpoison_slab_object mm/kasan/common.c:314 [inline]
__kasan_slab_alloc+0x66/0x70 mm/kasan/common.c:340
kasan_slab_alloc include/linux/kasan.h:201 [inline]
slab_post_alloc_hook mm/slub.c:3813 [inline]
slab_alloc_node mm/slub.c:3860 [inline]
kmem_cache_alloc+0x16f/0x340 mm/slub.c:3867
vm_area_alloc+0x24/0x1d0 kernel/fork.c:465
mmap_region+0xbd8/0x1f90 mm/mmap.c:2804
do_mmap+0x76b/0xde0 mm/mmap.c:1379
vm_mmap_pgoff+0x1e2/0x420 mm/util.c:556
ksys_mmap_pgoff+0x4ff/0x6d0 mm/mmap.c:1425
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xf5/0x230 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x63/0x6b

Freed by task 5064:
kasan_save_stack mm/kasan/common.c:47 [inline]
kasan_save_track+0x3f/0x70 mm/kasan/common.c:68
kasan_save_free_info+0x4e/0x60 mm/kasan/generic.c:634
poison_slab_object+0xa6/0xe0 mm/kasan/common.c:241
__kasan_slab_free+0x34/0x60 mm/kasan/common.c:257
kasan_slab_free include/linux/kasan.h:184 [inline]
slab_free_hook mm/slub.c:2121 [inline]
slab_free mm/slub.c:4299 [inline]
kmem_cache_free+0x102/0x2a0 mm/slub.c:4363
rcu_do_batch kernel/rcu/tree.c:2158 [inline]
rcu_core+0xad8/0x17c0 kernel/rcu/tree.c:2433
__do_softirq+0x2b8/0x939 kernel/softirq.c:553

Last potentially related work creation:
kasan_save_stack+0x3f/0x60 mm/kasan/common.c:47
__kasan_record_aux_stack+0xae/0x100 mm/kasan/generic.c:580
__call_rcu_common kernel/rcu/tree.c:2683 [inline]
call_rcu+0x167/0xa80 kernel/rcu/tree.c:2797
remove_vma mm/mmap.c:148 [inline]
remove_mt mm/mmap.c:2283 [inline]
do_vmi_align_munmap+0x159d/0x1930 mm/mmap.c:2629
do_vmi_munmap+0x24d/0x2d0 mm/mmap.c:2693
mmap_region+0x677/0x1f90 mm/mmap.c:2744
do_mmap+0x76b/0xde0 mm/mmap.c:1379
vm_mmap_pgoff+0x1e2/0x420 mm/util.c:556
ksys_mmap_pgoff+0x4ff/0x6d0 mm/mmap.c:1425
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xf5/0x230 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x63/0x6b

The buggy address belongs to the object at ffff88807bb22660
which belongs to the cache vm_area_struct of size 192
The buggy address is located 32 bytes inside of
freed 192-byte region [ffff88807bb22660, ffff88807bb22720)

The buggy address belongs to the physical page:
page:ffffea0001eec880 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x7bb22
flags: 0xfff00000000800(slab|node=0|zone=1|lastcpupid=0x7ff)
page_type: 0xffffffff()
raw: 00fff00000000800 ffff8880142a1b40 dead000000000122 0000000000000000
raw: 0000000000000000 00000000800f000f 00000001ffffffff 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 0x12cc0(GFP_KERNEL|__GFP_NOWARN|__GFP_NORETRY), pid 5039, tgid 5039 (sshd), ts 50202976366, free_ts 44674399535
set_page_owner include/linux/page_owner.h:31 [inline]
post_alloc_hook+0x1e6/0x210 mm/page_alloc.c:1533
prep_new_page mm/page_alloc.c:1540 [inline]
get_page_from_freelist+0x33ea/0x3570 mm/page_alloc.c:3311
__alloc_pages+0x255/0x680 mm/page_alloc.c:4567
__alloc_pages_node include/linux/gfp.h:238 [inline]
alloc_pages_node include/linux/gfp.h:261 [inline]
alloc_slab_page+0x5f/0x160 mm/slub.c:2190
allocate_slab mm/slub.c:2354 [inline]
new_slab+0x84/0x2f0 mm/slub.c:2407
___slab_alloc+0xd17/0x13d0 mm/slub.c:3540
__slab_alloc mm/slub.c:3625 [inline]
__slab_alloc_node mm/slub.c:3678 [inline]
slab_alloc_node mm/slub.c:3850 [inline]
kmem_cache_alloc+0x249/0x340 mm/slub.c:3867
vm_area_dup+0x27/0x280 kernel/fork.c:480
dup_mmap kernel/fork.c:695 [inline]
dup_mm kernel/fork.c:1685 [inline]
copy_mm+0xd90/0x21b0 kernel/fork.c:1734
copy_process+0x1d6f/0x3fb0 kernel/fork.c:2496
kernel_clone+0x222/0x840 kernel/fork.c:2901
__do_sys_clone kernel/fork.c:3044 [inline]
__se_sys_clone kernel/fork.c:3028 [inline]
__x64_sys_clone+0x258/0x2a0 kernel/fork.c:3028
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xf5/0x230 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x63/0x6b
page last free pid 5037 tgid 5037 stack trace:
reset_page_owner include/linux/page_owner.h:24 [inline]
free_pages_prepare mm/page_alloc.c:1140 [inline]
free_unref_page_prepare+0x959/0xa80 mm/page_alloc.c:2346
free_unref_page+0x37/0x3f0 mm/page_alloc.c:2486
pipe_buf_release include/linux/pipe_fs_i.h:219 [inline]
pipe_update_tail fs/pipe.c:234 [inline]
pipe_read+0x6ee/0x13e0 fs/pipe.c:354
call_read_iter include/linux/fs.h:2079 [inline]
new_sync_read fs/read_write.c:395 [inline]
vfs_read+0x662/0x900 fs/read_write.c:476
ksys_read+0x1a0/0x2c0 fs/read_write.c:619
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xf5/0x230 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x63/0x6b

Memory state around the buggy address:
ffff88807bb22580: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
ffff88807bb22600: 00 00 fc fc fc fc fc fc fc fc fc fc fa fb fb fb
>ffff88807bb22680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff88807bb22700: fb fb fb fb fc fc fc fc fc fc fc fc fc fc 00 00
ffff88807bb22780: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
==================================================================


---
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[Hillf Danton]

On Mon, 15 Jan 2024 01:12:17 -0800

> HEAD commit: 052d534373b7 Merge tag 'exfat-for-6.8-rc1' of git://git.ke..
> git tree: upstream

> C reproducer: https://syzkaller.appspot.com/x/repro.c?x=1422d5ebe80000

#syz test https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master

--- x/fs/f2fs/file.c
+++ y/fs/f2fs/file.c
@@ -39,6 +39,7 @@
static vm_fault_t f2fs_filemap_fault(struct vm_fault *vmf)
{
struct inode *inode = file_inode(vmf->vma->vm_file);
+ vm_flags_t flags = vmf->vma->vm_flags;
vm_fault_t ret;

ret = filemap_fault(vmf);
@@ -46,7 +47,7 @@ static vm_fault_t f2fs_filemap_fault(str
f2fs_update_iostat(F2FS_I_SB(inode), inode,
APP_MAPPED_READ_IO, F2FS_BLKSIZE);

- trace_f2fs_filemap_fault(inode, vmf->pgoff, vmf->vma->vm_flags, ret);
+ trace_f2fs_filemap_fault(inode, vmf->pgoff, flags, ret);

return ret;
}
--

[syzbot]

Hello,

syzbot has tested the proposed patch and the reproducer did not trigger any issue:

Reported-and-tested-by: syzbot+763afa...@syzkaller.appspotmail.com

Tested on:

commit: 052d5343 Merge tag 'exfat-for-6.8-rc1' of git://git.ke..
git tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
console output: https://syzkaller.appspot.com/x/log.txt?x=105a1a0be80000

kernel config: https://syzkaller.appspot.com/x/.config?x=490fc2f9d4ae426c
dashboard link: https://syzkaller.appspot.com/bug?extid=763afad57075d3f862f2
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40

patch: https://syzkaller.appspot.com/x/patch.diff?x=14a249b9e80000

Note: testing is done by a robot and is best-effort only.

[Chao Yu]

#syz test git://git.kernel.org/pub/scm/linux/kernel/git/chao/linux.git wip

[syzbot]

Hello,

syzbot has tested the proposed patch and the reproducer did not trigger any issue:

Reported-and-tested-by: syzbot+763afa...@syzkaller.appspotmail.com

Tested on:

commit: 51fc665a f2fs: fix to avoid use-after-free issue in f2..
git tree: git://git.kernel.org/pub/scm/linux/kernel/git/chao/linux.git wip
console output: https://syzkaller.appspot.com/x/log.txt?x=113bf9fa180000
kernel config: https://syzkaller.appspot.com/x/.config?x=1fcc0a6ff51770e5

dashboard link: https://syzkaller.appspot.com/bug?extid=763afad57075d3f862f2
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40

Note: no patches were applied.