Re: [syzbot] [ext4?] KASAN: slab-use-after-free Read in ext4_convert_inline_data_nolock

From: syzbot
Date: Tue Mar 28 2023 - 03:54:10 EST

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In reply to: syzbot: "[syzbot] [ext4?] KASAN: slab-use-after-free Read in ext4_convert_inline_data_nolock"
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syzbot has found a reproducer for the following issue on:

HEAD commit: 3a93e40326c8 Merge tag 'for-linus' of git://git.kernel.org..
git tree: upstream
console+strace: https://syzkaller.appspot.com/x/log.txt?x=1034aed5c80000
kernel config: https://syzkaller.appspot.com/x/.config?x=9c35b3803e5ad668
dashboard link: https://syzkaller.appspot.com/bug?extid=db6caad9ebd2c8022b41
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=11a2cd05c80000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=158e1f29c80000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/65fe3e7679b9/disk-3a93e403.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/169220ad146c/vmlinux-3a93e403.xz
kernel image: https://storage.googleapis.com/syzbot-assets/6f5e2d192c51/bzImage-3a93e403.xz
mounted in repro: https://storage.googleapis.com/syzbot-assets/343663881b01/mount_0.gz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+db6caad9ebd2c8022b41@xxxxxxxxxxxxxxxxxxxxxxxxx

EXT4-fs (loop0): mounted filesystem 00000000-0000-0000-0000-000000000000 without journal. Quota mode: none.
==================================================================
BUG: KASAN: slab-out-of-bounds in ext4_read_inline_data fs/ext4/inline.c:199 [inline]
BUG: KASAN: slab-out-of-bounds in ext4_convert_inline_data_nolock+0x31a/0xd80 fs/ext4/inline.c:1204
Read of size 20 at addr ffff88807645e1a3 by task syz-executor378/5075

CPU: 0 PID: 5075 Comm: syz-executor378 Not tainted 6.3.0-rc4-syzkaller-00025-g3a93e40326c8 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/02/2023
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:319 [inline]
print_report+0x163/0x540 mm/kasan/report.c:430
kasan_report+0x176/0x1b0 mm/kasan/report.c:536
kasan_check_range+0x283/0x290 mm/kasan/generic.c:187
__asan_memcpy+0x29/0x70 mm/kasan/shadow.c:105
ext4_read_inline_data fs/ext4/inline.c:199 [inline]
ext4_convert_inline_data_nolock+0x31a/0xd80 fs/ext4/inline.c:1204
ext4_convert_inline_data+0x4da/0x620 fs/ext4/inline.c:2065
ext4_fallocate+0x14d/0x2050 fs/ext4/extents.c:4701
vfs_fallocate+0x54b/0x6b0 fs/open.c:324
ksys_fallocate fs/open.c:347 [inline]
__do_sys_fallocate fs/open.c:355 [inline]
__se_sys_fallocate fs/open.c:353 [inline]
__x64_sys_fallocate+0xbd/0x100 fs/open.c:353
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7fb0579425c9
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 31 18 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:00007ffdcef99758 EFLAGS: 00000246 ORIG_RAX: 000000000000011d
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fb0579425c9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000004
RBP: 0000000000000003 R08: 0000000000000003 R09: 0000000000000003
R10: 0000000000008000 R11: 0000000000000246 R12: 00007ffdcef99790
R13: 00007ffdcef99788 R14: 00007ffdcef99784 R15: 0000000000000003
</TASK>

Allocated by task 5023:
kasan_save_stack mm/kasan/common.c:45 [inline]
kasan_set_track+0x4f/0x70 mm/kasan/common.c:52
__kasan_slab_alloc+0x66/0x70 mm/kasan/common.c:328
kasan_slab_alloc include/linux/kasan.h:186 [inline]
slab_post_alloc_hook+0x68/0x3a0 mm/slab.h:769
slab_alloc_node mm/slub.c:3452 [inline]
slab_alloc mm/slub.c:3460 [inline]
__kmem_cache_alloc_lru mm/slub.c:3467 [inline]
kmem_cache_alloc+0x11f/0x2e0 mm/slub.c:3476
mt_alloc_one lib/maple_tree.c:159 [inline]
mas_alloc_nodes+0x26e/0x780 lib/maple_tree.c:1233
mas_node_count_gfp lib/maple_tree.c:1318 [inline]
mas_preallocate+0x131/0x350 lib/maple_tree.c:5717
vma_iter_prealloc mm/internal.h:972 [inline]
__split_vma+0x1e0/0x7f0 mm/mmap.c:2177
mprotect_fixup+0x5f5/0x920 mm/mprotect.c:663
do_mprotect_pkey+0x8f8/0xc60 mm/mprotect.c:831
__do_sys_mprotect mm/mprotect.c:852 [inline]
__se_sys_mprotect mm/mprotect.c:849 [inline]
__x64_sys_mprotect+0x80/0x90 mm/mprotect.c:849
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd

Freed by task 5023:
kasan_save_stack mm/kasan/common.c:45 [inline]
kasan_set_track+0x4f/0x70 mm/kasan/common.c:52
kasan_save_free_info+0x2b/0x40 mm/kasan/generic.c:521
____kasan_slab_free+0xd6/0x120 mm/kasan/common.c:236
kasan_slab_free include/linux/kasan.h:162 [inline]
slab_free_hook mm/slub.c:1781 [inline]
slab_free_freelist_hook mm/slub.c:1807 [inline]
slab_free mm/slub.c:3787 [inline]
kmem_cache_free+0x297/0x520 mm/slub.c:3809
mas_destroy+0x1bdc/0x2280 lib/maple_tree.c:5774
mas_store_prealloc+0x351/0x460 lib/maple_tree.c:5702
vma_complete+0x1ed/0x970 mm/mmap.c:572
__split_vma+0x7b9/0x7f0 mm/mmap.c:2214
mprotect_fixup+0x5f5/0x920 mm/mprotect.c:663
do_mprotect_pkey+0x8f8/0xc60 mm/mprotect.c:831
__do_sys_mprotect mm/mprotect.c:852 [inline]
__se_sys_mprotect mm/mprotect.c:849 [inline]
__x64_sys_mprotect+0x80/0x90 mm/mprotect.c:849
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd

The buggy address belongs to the object at ffff88807645e000
which belongs to the cache maple_node of size 256
The buggy address is located 163 bytes to the right of
allocated 256-byte region [ffff88807645e000, ffff88807645e100)

The buggy address belongs to the physical page:
page:ffffea0001d91780 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x7645e
head:ffffea0001d91780 order:1 entire_mapcount:0 nr_pages_mapped:0 pincount:0
flags: 0xfff00000010200(slab|head|node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000010200 ffff8880124cd000 dead000000000122 0000000000000000
raw: 0000000000000000 0000000000100010 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 1, migratetype Unmovable, gfp_mask 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 5023, tgid 5023 (rm), ts 57145564531, free_ts 41308598324
prep_new_page mm/page_alloc.c:2553 [inline]
get_page_from_freelist+0x3246/0x33c0 mm/page_alloc.c:4326
__alloc_pages+0x255/0x670 mm/page_alloc.c:5592
alloc_slab_page+0x6a/0x160 mm/slub.c:1851
allocate_slab mm/slub.c:1998 [inline]
new_slab+0x84/0x2f0 mm/slub.c:2051
___slab_alloc+0xa85/0x10a0 mm/slub.c:3193
__slab_alloc mm/slub.c:3292 [inline]
__slab_alloc_node mm/slub.c:3345 [inline]
slab_alloc_node mm/slub.c:3442 [inline]
slab_alloc mm/slub.c:3460 [inline]
__kmem_cache_alloc_lru mm/slub.c:3467 [inline]
kmem_cache_alloc+0x1b9/0x2e0 mm/slub.c:3476
mt_alloc_one lib/maple_tree.c:159 [inline]
mas_alloc_nodes+0x26e/0x780 lib/maple_tree.c:1233
mas_node_count_gfp lib/maple_tree.c:1318 [inline]
mas_preallocate+0x131/0x350 lib/maple_tree.c:5717
vma_iter_prealloc mm/internal.h:972 [inline]
__split_vma+0x1e0/0x7f0 mm/mmap.c:2177
mprotect_fixup+0x5f5/0x920 mm/mprotect.c:663
do_mprotect_pkey+0x8f8/0xc60 mm/mprotect.c:831
__do_sys_mprotect mm/mprotect.c:852 [inline]
__se_sys_mprotect mm/mprotect.c:849 [inline]
__x64_sys_mprotect+0x80/0x90 mm/mprotect.c:849
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x41/0xc0 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:1454 [inline]
free_pcp_prepare mm/page_alloc.c:1504 [inline]
free_unref_page_prepare+0xe2f/0xe70 mm/page_alloc.c:3388
free_unref_page+0x37/0x3f0 mm/page_alloc.c:3483
discard_slab mm/slub.c:2098 [inline]
__unfreeze_partials+0x1b1/0x1f0 mm/slub.c:2637
put_cpu_partial+0x116/0x180 mm/slub.c:2713
qlist_free_all+0x22/0x60 mm/kasan/quarantine.c:187
kasan_quarantine_reduce+0x14b/0x160 mm/kasan/quarantine.c:294
__kasan_slab_alloc+0x23/0x70 mm/kasan/common.c:305
kasan_slab_alloc include/linux/kasan.h:186 [inline]
slab_post_alloc_hook+0x68/0x3a0 mm/slab.h:769
slab_alloc_node mm/slub.c:3452 [inline]
slab_alloc mm/slub.c:3460 [inline]
__kmem_cache_alloc_lru mm/slub.c:3467 [inline]
kmem_cache_alloc+0x11f/0x2e0 mm/slub.c:3476
vm_area_alloc+0x24/0xe0 kernel/fork.c:458
mmap_region+0xbfb/0x20c0 mm/mmap.c:2553
do_mmap+0x8c9/0xf70 mm/mmap.c:1364
vm_mmap_pgoff+0x1ce/0x2e0 mm/util.c:542
ksys_mmap_pgoff+0x4f9/0x6d0 mm/mmap.c:1410
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd

Memory state around the buggy address:
ffff88807645e080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff88807645e100: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff88807645e180: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
^
ffff88807645e200: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff88807645e280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================

Next message: Jan Kara: "Re: [PATCH 3/3] fanotify: use pidfd_prepare()"
Previous message: Roger Quadros: "Re: [PATCH v7 3/3] remoteproc: k3-r5: Use separate compatible string for TI AM62x SoC family"
In reply to: syzbot: "[syzbot] [ext4?] KASAN: slab-use-after-free Read in ext4_convert_inline_data_nolock"
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