[v6.1] KASAN: use-after-free Read in ext4_convert_inline_data_nolock

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 0102425ac76b Linux 6.1.24
git tree: linux-6.1.y
console output: https://syzkaller.appspot.com/x/log.txt?x=118f0eebc80000
kernel config: https://syzkaller.appspot.com/x/.config?x=cb976cea3176ce66
dashboard link: https://syzkaller.appspot.com/bug?extid=824b138c39c77ad6775f
compiler: Debian clang version 15.0.7, GNU ld (GNU Binutils for Debian) 2.35.2

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/2bbac2ad18f4/disk-0102425a.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/9000ac7a5566/vmlinux-0102425a.xz
kernel image: https://storage.googleapis.com/syzbot-assets/08367306fcea/bzImage-0102425a.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+824b13...@syzkaller.appspotmail.com

==================================================================
BUG: KASAN: use-after-free in ext4_read_inline_data fs/ext4/inline.c:200 [inline]
BUG: KASAN: use-after-free in ext4_convert_inline_data_nolock+0x319/0xda0 fs/ext4/inline.c:1205
Read of size 20 at addr ffff88807a5a81a3 by task syz-executor.0/15401

CPU: 1 PID: 15401 Comm: syz-executor.0 Not tainted 6.1.24-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/30/2023
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0x1e3/0x2cb lib/dump_stack.c:106
print_address_description mm/kasan/report.c:284 [inline]
print_report+0x15f/0x4f0 mm/kasan/report.c:395
kasan_report+0x136/0x160 mm/kasan/report.c:495
kasan_check_range+0x27f/0x290 mm/kasan/generic.c:189
memcpy+0x25/0x60 mm/kasan/shadow.c:65
ext4_read_inline_data fs/ext4/inline.c:200 [inline]
ext4_convert_inline_data_nolock+0x319/0xda0 fs/ext4/inline.c:1205
ext4_convert_inline_data+0x4cf/0x610 fs/ext4/inline.c:2066
ext4_fallocate+0x149/0x2160 fs/ext4/extents.c:4702
vfs_fallocate+0x547/0x6b0 fs/open.c:323
ksys_fallocate fs/open.c:346 [inline]
__do_sys_fallocate fs/open.c:354 [inline]
__se_sys_fallocate fs/open.c:352 [inline]
__x64_sys_fallocate+0xb9/0x100 fs/open.c:352
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7fc41808c169
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 f1 19 00 00 90 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 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fc418dbd168 EFLAGS: 00000246 ORIG_RAX: 000000000000011d
RAX: ffffffffffffffda RBX: 00007fc4181ac050 RCX: 00007fc41808c169
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000004
RBP: 00007fc4180e7ca1 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000008000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ffeee318e7f R14: 00007fc418dbd300 R15: 0000000000022000
</TASK>

The buggy address belongs to the physical page:
page:ffffea0001e96a00 refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x7a5a8
flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000000000 ffffea000079d708 ffffea0001d36ec8 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 0, migratetype Unmovable, gfp_mask 0x100cc0(GFP_USER), pid 2, tgid 2 (kthreadd), ts 543524215802, free_ts 558698489427
prep_new_page mm/page_alloc.c:2540 [inline]
get_page_from_freelist+0x32ed/0x3480 mm/page_alloc.c:4292
__alloc_pages+0x28d/0x770 mm/page_alloc.c:5559
__get_free_pages+0x8/0x30 mm/page_alloc.c:5609
kasan_populate_vmalloc_pte+0x2a/0xd0 mm/kasan/shadow.c:271
apply_to_pte_range mm/memory.c:2635 [inline]
apply_to_pmd_range mm/memory.c:2679 [inline]
apply_to_pud_range mm/memory.c:2715 [inline]
apply_to_p4d_range mm/memory.c:2751 [inline]
__apply_to_page_range+0x9c5/0xcc0 mm/memory.c:2785
alloc_vmap_area+0x1977/0x1ac0 mm/vmalloc.c:1642
__get_vm_area_node+0x16c/0x360 mm/vmalloc.c:2501
__vmalloc_node_range+0x394/0x1460 mm/vmalloc.c:3175
alloc_thread_stack_node kernel/fork.c:311 [inline]
dup_task_struct+0x3e5/0x6d0 kernel/fork.c:980
copy_process+0x637/0x4020 kernel/fork.c:2090
kernel_clone+0x222/0x920 kernel/fork.c:2679
kernel_thread+0x152/0x1d0 kernel/fork.c:2739
create_kthread kernel/kthread.c:399 [inline]
kthreadd+0x577/0x740 kernel/kthread.c:746
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:306
page last free stack trace:
reset_page_owner include/linux/page_owner.h:24 [inline]
free_pages_prepare mm/page_alloc.c:1460 [inline]
free_pcp_prepare mm/page_alloc.c:1510 [inline]
free_unref_page_prepare+0xf5e/0x1110 mm/page_alloc.c:3388
free_unref_page+0x98/0x570 mm/page_alloc.c:3484
kasan_depopulate_vmalloc_pte+0x66/0x80 mm/kasan/shadow.c:375
apply_to_pte_range mm/memory.c:2635 [inline]
apply_to_pmd_range mm/memory.c:2679 [inline]
apply_to_pud_range mm/memory.c:2715 [inline]
apply_to_p4d_range mm/memory.c:2751 [inline]
__apply_to_page_range+0x9c5/0xcc0 mm/memory.c:2785
kasan_release_vmalloc+0x96/0xb0 mm/kasan/shadow.c:492
__purge_vmap_area_lazy+0x157c/0x1720 mm/vmalloc.c:1770
drain_vmap_area_work+0x3c/0xd0 mm/vmalloc.c:1799
process_one_work+0x8aa/0x11f0 kernel/workqueue.c:2289
worker_thread+0xa5f/0x1210 kernel/workqueue.c:2436
kthread+0x268/0x300 kernel/kthread.c:376
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:306

Memory state around the buggy address:
ffff88807a5a8080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
ffff88807a5a8100: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
>ffff88807a5a8180: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
^
ffff88807a5a8200: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
ffff88807a5a8280: 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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syzbot will keep track of this issue. See:
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[syzbot]

syzbot has found a reproducer for the following issue on:

HEAD commit: fa74641fb6b9 Linux 6.1.29
git tree: linux-6.1.y
console output: https://syzkaller.appspot.com/x/log.txt?x=152e4b72280000
kernel config: https://syzkaller.appspot.com/x/.config?x=fac5c36c2b16009f

dashboard link: https://syzkaller.appspot.com/bug?extid=824b138c39c77ad6775f
compiler: Debian clang version 15.0.7, GNU ld (GNU Binutils for Debian) 2.35.2

syz repro: https://syzkaller.appspot.com/x/repro.syz?x=12c50236280000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=16d8b7a1280000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/3e78f005d7f8/disk-fa74641f.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/6527fcf66401/vmlinux-fa74641f.xz
kernel image: https://storage.googleapis.com/syzbot-assets/c5e0d5f8b434/bzImage-fa74641f.xz
mounted in repro: https://storage.googleapis.com/syzbot-assets/0d052a081a48/mount_0.gz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+824b13...@syzkaller.appspotmail.com

loop0: detected capacity change from 0 to 2048
EXT4-fs (loop0): mounted filesystem without journal. Quota mode: none.
==================================================================
BUG: KASAN: slab-out-of-bounds in ext4_read_inline_data fs/ext4/inline.c:210 [inline]
BUG: KASAN: slab-out-of-bounds in ext4_convert_inline_data_nolock+0x319/0xda0 fs/ext4/inline.c:1216
Read of size 20 at addr ffff888021fc41a3 by task syz-executor200/3543

CPU: 1 PID: 3543 Comm: syz-executor200 Not tainted 6.1.29-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/28/2023

Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0x1e3/0x2cb lib/dump_stack.c:106
print_address_description mm/kasan/report.c:284 [inline]
print_report+0x15f/0x4f0 mm/kasan/report.c:395
kasan_report+0x136/0x160 mm/kasan/report.c:495
kasan_check_range+0x27f/0x290 mm/kasan/generic.c:189
memcpy+0x25/0x60 mm/kasan/shadow.c:65

ext4_read_inline_data fs/ext4/inline.c:210 [inline]
ext4_convert_inline_data_nolock+0x319/0xda0 fs/ext4/inline.c:1216
ext4_convert_inline_data+0x4cf/0x610 fs/ext4/inline.c:2077

ext4_fallocate+0x149/0x2160 fs/ext4/extents.c:4702
vfs_fallocate+0x547/0x6b0 fs/open.c:323
ksys_fallocate fs/open.c:346 [inline]
__do_sys_fallocate fs/open.c:354 [inline]
__se_sys_fallocate fs/open.c:352 [inline]
__x64_sys_fallocate+0xb9/0x100 fs/open.c:352
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd

RIP: 0033:0x7fd1575f3059
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 71 17 00 00 90 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 c0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fffbd64e728 EFLAGS: 00000246 ORIG_RAX: 000000000000011d
RAX: ffffffffffffffda RBX: 00007fd157661720 RCX: 00007fd1575f3059

RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000004

RBP: 0000000000000001 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000008000 R11: 0000000000000246 R12: 0000000000000004
R13: 0000000000000003 R14: 00007fffbd64e760 R15: 000000000000000c
</TASK>

Allocated by task 3397:
kasan_save_stack mm/kasan/common.c:45 [inline]
kasan_set_track+0x4b/0x70 mm/kasan/common.c:52
__kasan_slab_alloc+0x65/0x70 mm/kasan/common.c:328
kasan_slab_alloc include/linux/kasan.h:201 [inline]
slab_post_alloc_hook+0x50/0x370 mm/slab.h:737
slab_alloc_node mm/slub.c:3398 [inline]
slab_alloc mm/slub.c:3406 [inline]
__kmem_cache_alloc_lru mm/slub.c:3413 [inline]
kmem_cache_alloc+0x10c/0x2d0 mm/slub.c:3422
vm_area_dup+0x23/0x1b0 kernel/fork.c:466
dup_mmap kernel/fork.c:644 [inline]
dup_mm+0xa7c/0x1610 kernel/fork.c:1532
copy_mm+0xca/0x160 kernel/fork.c:1581
copy_process+0x19a2/0x4020 kernel/fork.c:2259
kernel_clone+0x222/0x920 kernel/fork.c:2679
__do_sys_clone kernel/fork.c:2820 [inline]
__se_sys_clone kernel/fork.c:2804 [inline]
__x64_sys_clone+0x231/0x280 kernel/fork.c:2804

do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd

Freed by task 3398:
kasan_save_stack mm/kasan/common.c:45 [inline]
kasan_set_track+0x4b/0x70 mm/kasan/common.c:52
kasan_save_free_info+0x27/0x40 mm/kasan/generic.c:516
____kasan_slab_free+0xd6/0x120 mm/kasan/common.c:236
kasan_slab_free include/linux/kasan.h:177 [inline]
slab_free_hook mm/slub.c:1724 [inline]
slab_free_freelist_hook mm/slub.c:1750 [inline]
slab_free mm/slub.c:3661 [inline]
kmem_cache_free+0x292/0x510 mm/slub.c:3683
remove_vma mm/mmap.c:144 [inline]
exit_mmap+0x538/0x9f0 mm/mmap.c:3149
__mmput+0x115/0x3c0 kernel/fork.c:1191
exit_mm+0x226/0x300 kernel/exit.c:563
do_exit+0x67e/0x2300 kernel/exit.c:856
do_group_exit+0x202/0x2b0 kernel/exit.c:1019
__do_sys_exit_group kernel/exit.c:1030 [inline]
__se_sys_exit_group kernel/exit.c:1028 [inline]
__x64_sys_exit_group+0x3b/0x40 kernel/exit.c:1028

do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd

The buggy address belongs to the object at ffff888021fc40d8
which belongs to the cache vm_area_struct of size 152
The buggy address is located 51 bytes to the right of
152-byte region [ffff888021fc40d8, ffff888021fc4170)

The buggy address belongs to the physical page:

page:ffffea000087f100 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x21fc4
flags: 0xfff00000000200(slab|node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000000200 0000000000000000 dead000000000122 ffff888140007b40
raw: 0000000000000000 0000000000120012 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 3397, tgid 3397 (sshd), ts 46628352006, free_ts 45979203794
set_page_owner include/linux/page_owner.h:31 [inline]
post_alloc_hook+0x18d/0x1b0 mm/page_alloc.c:2533

prep_new_page mm/page_alloc.c:2540 [inline]
get_page_from_freelist+0x32ed/0x3480 mm/page_alloc.c:4292
__alloc_pages+0x28d/0x770 mm/page_alloc.c:5559

alloc_slab_page+0x6a/0x150 mm/slub.c:1794
allocate_slab mm/slub.c:1939 [inline]
new_slab+0x84/0x2d0 mm/slub.c:1992
___slab_alloc+0xa71/0x1080 mm/slub.c:3180
__slab_alloc mm/slub.c:3279 [inline]
slab_alloc_node mm/slub.c:3364 [inline]
slab_alloc mm/slub.c:3406 [inline]
__kmem_cache_alloc_lru mm/slub.c:3413 [inline]
kmem_cache_alloc+0x1a5/0x2d0 mm/slub.c:3422
vm_area_dup+0x23/0x1b0 kernel/fork.c:466
dup_mmap kernel/fork.c:644 [inline]
dup_mm+0xa7c/0x1610 kernel/fork.c:1532
copy_mm+0xca/0x160 kernel/fork.c:1581
copy_process+0x19a2/0x4020 kernel/fork.c:2259
kernel_clone+0x222/0x920 kernel/fork.c:2679
__do_sys_clone kernel/fork.c:2820 [inline]
__se_sys_clone kernel/fork.c:2804 [inline]
__x64_sys_clone+0x231/0x280 kernel/fork.c:2804

do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd

page last free stack trace:
reset_page_owner include/linux/page_owner.h:24 [inline]
free_pages_prepare mm/page_alloc.c:1460 [inline]
free_pcp_prepare mm/page_alloc.c:1510 [inline]

free_unref_page_prepare+0xf63/0x1120 mm/page_alloc.c:3388
free_unref_page_list+0x107/0x810 mm/page_alloc.c:3530
release_pages+0x2836/0x2b40 mm/swap.c:1055
tlb_batch_pages_flush mm/mmu_gather.c:59 [inline]
tlb_flush_mmu_free mm/mmu_gather.c:254 [inline]
tlb_flush_mmu+0xfc/0x210 mm/mmu_gather.c:261
tlb_finish_mmu+0xce/0x1f0 mm/mmu_gather.c:361
exit_mmap+0x3c3/0x9f0 mm/mmap.c:3139
__mmput+0x115/0x3c0 kernel/fork.c:1191
exit_mm+0x226/0x300 kernel/exit.c:563
do_exit+0x67e/0x2300 kernel/exit.c:856
do_group_exit+0x202/0x2b0 kernel/exit.c:1019
__do_sys_exit_group kernel/exit.c:1030 [inline]
__se_sys_exit_group kernel/exit.c:1028 [inline]
__x64_sys_exit_group+0x3b/0x40 kernel/exit.c:1028

do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd

Memory state around the buggy address:

ffff888021fc4080: fb fb fb fc fc fc fc fc fc fc fc fa fb fb fb fb
ffff888021fc4100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fc fc
>ffff888021fc4180: fc fc fc fc fc fc fa fb fb fb fb fb fb fb fb fb
^
ffff888021fc4200: fb fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc
ffff888021fc4280: fc fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================


---
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