syzbot


KASAN: use-after-free Read in ocfs2_dir_foreach_blk

Status: upstream: reported C repro on 2025/02/03 04:13
Reported-by: syzbot+207f6ce08909b626016f@syzkaller.appspotmail.com
First crash: 2d03h, last: 2d02h
Bug presence (1)
Date Name Commit Repro Result
2025/02/03 upstream (ToT) 2014c95afece C Failed due to an error; will retry later
Similar bugs (1)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream KASAN: use-after-free Read in ocfs2_dir_foreach_blk ocfs2 C 43 16m 130d 0/28 upstream: reported C repro on 2024/09/27 14:22

Sample crash report:
WARNING: The mand mount option has been deprecated and
         and is ignored by this kernel. Remove the mand
         option from the mount to silence this warning.
=======================================================
ocfs2: Mounting device (7,0) on (node local, slot 0) with ordered data mode.
==================================================================
BUG: KASAN: use-after-free in ocfs2_dir_foreach_blk_id fs/ocfs2/dir.c:1776 [inline]
BUG: KASAN: use-after-free in ocfs2_dir_foreach_blk+0x14f8/0x1e10 fs/ocfs2/dir.c:1914
Read of size 2 at addr ffff88806ecc88c9 by task syz-executor260/4249

CPU: 1 PID: 4249 Comm: syz-executor260 Not tainted 6.1.128-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 12/27/2024
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:316 [inline]
 print_report+0x15f/0x4f0 mm/kasan/report.c:427
 kasan_report+0x136/0x160 mm/kasan/report.c:531
 ocfs2_dir_foreach_blk_id fs/ocfs2/dir.c:1776 [inline]
 ocfs2_dir_foreach_blk+0x14f8/0x1e10 fs/ocfs2/dir.c:1914
 ocfs2_readdir+0x28a/0x620 fs/ocfs2/dir.c:1957
 iterate_dir+0x224/0x560
 __do_sys_getdents fs/readdir.c:286 [inline]
 __se_sys_getdents+0x1eb/0x4c0 fs/readdir.c:271
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f697ab7e0e9
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 71 1d 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 b0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffe36559f78 EFLAGS: 00000246 ORIG_RAX: 000000000000004e
RAX: ffffffffffffffda RBX: 6f6c666c61636f6c RCX: 00007f697ab7e0e9
RDX: 0000000000000054 RSI: 0000000000000000 RDI: 0000000000000004
RBP: 00007f697abcb5e7 R08: 0000000000000004 R09: 0000000000000004
R10: 0000000000000004 R11: 0000000000000246 R12: 00007f697abcb568
R13: 00007ffe3655a000 R14: 00007f697ac05740 R15: 00007ffe36559fd8
 </TASK>

The buggy address belongs to the physical page:
page:ffffea0001bb3200 refcount:0 mapcount:0 mapping:0000000000000000 index:0x1 pfn:0x6ecc8
flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000000000 ffffea0001bb3248 ffffea0001bb31c8 0000000000000000
raw: 0000000000000001 0000000000000000 00000000ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as freed
page last allocated via order 0, migratetype Movable, gfp_mask 0x8(__GFP_MOVABLE), pid 1, tgid 1 (swapper/0), ts 19735888832, free_ts 21162749813
 set_page_owner include/linux/page_owner.h:31 [inline]
 post_alloc_hook+0x18d/0x1b0 mm/page_alloc.c:2532
 split_map_pages+0x246/0x510 mm/compaction.c:97
 isolate_freepages_range+0x47c/0x4e0 mm/compaction.c:735
 alloc_contig_range+0x62a/0x990 mm/page_alloc.c:9440
 __alloc_contig_pages mm/page_alloc.c:9463 [inline]
 alloc_contig_pages+0x3f0/0x4e0 mm/page_alloc.c:9543
 debug_vm_pgtable_alloc_huge_page+0xb9/0x108 mm/debug_vm_pgtable.c:1098
 init_args+0xc92/0x1022 mm/debug_vm_pgtable.c:1221
 debug_vm_pgtable+0xaa/0x46b mm/debug_vm_pgtable.c:1259
 do_one_initcall+0x265/0x8f0 init/main.c:1298
 do_initcall_level+0x157/0x207 init/main.c:1371
 do_initcalls+0x49/0x86 init/main.c:1387
 kernel_init_freeable+0x45c/0x60f init/main.c:1626
 kernel_init+0x19/0x290 init/main.c:1514
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
page last free stack trace:
 reset_page_owner include/linux/page_owner.h:24 [inline]
 free_pages_prepare mm/page_alloc.c:1459 [inline]
 free_pcp_prepare mm/page_alloc.c:1509 [inline]
 free_unref_page_prepare+0x12a6/0x15b0 mm/page_alloc.c:3384
 free_unref_page+0x33/0x3e0 mm/page_alloc.c:3479
 free_contig_range+0x9a/0x150 mm/page_alloc.c:9565
 destroy_args+0xfe/0x997 mm/debug_vm_pgtable.c:1031
 debug_vm_pgtable+0x416/0x46b mm/debug_vm_pgtable.c:1354
 do_one_initcall+0x265/0x8f0 init/main.c:1298
 do_initcall_level+0x157/0x207 init/main.c:1371
 do_initcalls+0x49/0x86 init/main.c:1387
 kernel_init_freeable+0x45c/0x60f init/main.c:1626
 kernel_init+0x19/0x290 init/main.c:1514
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295

Memory state around the buggy address:
 ffff88806ecc8780: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff88806ecc8800: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
>ffff88806ecc8880: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                                              ^
 ffff88806ecc8900: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff88806ecc8980: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
==================================================================

Crashes (3):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/02/03 05:13 linux-6.1.y 0cbb5f65e52f 568559e4 .config console log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro] ci2-linux-6-1-kasan KASAN: use-after-free Read in ocfs2_dir_foreach_blk
2025/02/03 04:38 linux-6.1.y 0cbb5f65e52f 568559e4 .config console log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro] ci2-linux-6-1-kasan KASAN: use-after-free Read in ocfs2_dir_foreach_blk
2025/02/03 04:12 linux-6.1.y 0cbb5f65e52f 568559e4 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan KASAN: use-after-free Read in ocfs2_dir_foreach_blk
* Struck through repros no longer work on HEAD.