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KASAN: slab-out-of-bounds Read in build_segment_manager

Status: fixed on 2018/07/09 18:05
Subsystems: f2fs
[Documentation on labels]
Reported-by: syzbot+0a725420475916460f12@syzkaller.appspotmail.com
Fix commit: 8a29c1260e24 f2fs: sanity check for total valid node blocks
First crash: 2426d, last: 2426d
▶ ▼ Discussions (4)
Title Replies (including bot) Last reply
[PATCH 4.14 000/217] 4.14.67-stable review 213 (213) 2018/08/24 05:19
[PATCH 4.17 00/67] 4.17.7-stable review 74 (74) 2018/07/17 09:41
[PATCH 1/5] f2fs: give message and set need_fsck given broken node id 16 (16) 2018/04/27 01:52
KASAN: slab-out-of-bounds Read in build_segment_manager 0 (1) 2018/04/20 16:55
▶ ▼ Similar bugs (2)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-4.14 KASAN: slab-out-of-bounds Read in build_segment_manager f2fs C error 5 670d 1527d 0/1 upstream: reported C repro on 2020/10/05 08:04
android-49 KASAN: slab-out-of-bounds Read in build_segment_manager C 1 2426d 2426d 0/3 closed as invalid on 2020/03/24 18:50

Sample crash report:
F2FS-fs (loop0): Magic Mismatch, valid(0xf2f52010) - read(0x0)
F2FS-fs (loop0): Can't find valid F2FS filesystem in 1th superblock
F2FS-fs (loop0): invalid crc value
==================================================================
BUG: KASAN: slab-out-of-bounds in build_sit_entries fs/f2fs/segment.c:3653 [inline]
BUG: KASAN: slab-out-of-bounds in build_segment_manager+0xb92d/0xbf70 fs/f2fs/segment.c:3852
Read of size 4 at addr ffff8801ac7b66e0 by task syzkaller806281/4519

CPU: 0 PID: 4519 Comm: syzkaller806281 Not tainted 4.17.0-rc1+ #8
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x1b9/0x294 lib/dump_stack.c:113
 print_address_description+0x6c/0x20b mm/kasan/report.c:256
 kasan_report_error mm/kasan/report.c:354 [inline]
 kasan_report.cold.7+0x242/0x2fe mm/kasan/report.c:412
 __asan_report_load4_noabort+0x14/0x20 mm/kasan/report.c:432
 build_sit_entries fs/f2fs/segment.c:3653 [inline]
 build_segment_manager+0xb92d/0xbf70 fs/f2fs/segment.c:3852
 f2fs_fill_super+0x4095/0x7bf0 fs/f2fs/super.c:2803
 mount_bdev+0x30c/0x3e0 fs/super.c:1165
 f2fs_mount+0x34/0x40 fs/f2fs/super.c:3020
 mount_fs+0xae/0x328 fs/super.c:1268
 vfs_kern_mount.part.34+0xd4/0x4d0 fs/namespace.c:1037
 vfs_kern_mount fs/namespace.c:1027 [inline]
 do_new_mount fs/namespace.c:2517 [inline]
 do_mount+0x564/0x3070 fs/namespace.c:2847
 ksys_mount+0x12d/0x140 fs/namespace.c:3063
 __do_sys_mount fs/namespace.c:3077 [inline]
 __se_sys_mount fs/namespace.c:3074 [inline]
 __x64_sys_mount+0xbe/0x150 fs/namespace.c:3074
 do_syscall_64+0x1b1/0x800 arch/x86/entry/common.c:287
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x4477ca
RSP: 002b:00007fff69213888 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 0000000020000b70 RCX: 00000000004477ca
RDX: 0000000020000000 RSI: 0000000020000100 RDI: 00007fff692138c0
RBP: 0000000000000064 R08: 0000000020016600 R09: 000000000000000a
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000064
R13: 0000000000000003 R14: 0000000000000000 R15: 0000000000000000

Allocated by task 2845:
 save_stack+0x43/0xd0 mm/kasan/kasan.c:448
 set_track mm/kasan/kasan.c:460 [inline]
 kasan_kmalloc+0xc4/0xe0 mm/kasan/kasan.c:553
 kasan_slab_alloc+0x12/0x20 mm/kasan/kasan.c:490
 kmem_cache_alloc+0x12e/0x760 mm/slab.c:3554
 getname_flags+0xd0/0x5a0 fs/namei.c:140
 getname+0x19/0x20 fs/namei.c:211
 do_sys_open+0x39a/0x740 fs/open.c:1087
 __do_sys_open fs/open.c:1111 [inline]
 __se_sys_open fs/open.c:1106 [inline]
 __x64_sys_open+0x7e/0xc0 fs/open.c:1106
 do_syscall_64+0x1b1/0x800 arch/x86/entry/common.c:287
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

Freed by task 2845:
 save_stack+0x43/0xd0 mm/kasan/kasan.c:448
 set_track mm/kasan/kasan.c:460 [inline]
 __kasan_slab_free+0x11a/0x170 mm/kasan/kasan.c:521
 kasan_slab_free+0xe/0x10 mm/kasan/kasan.c:528
 __cache_free mm/slab.c:3498 [inline]
 kmem_cache_free+0x86/0x2d0 mm/slab.c:3756
 putname+0xf2/0x130 fs/namei.c:261
 do_sys_open+0x554/0x740 fs/open.c:1102
 __do_sys_open fs/open.c:1111 [inline]
 __se_sys_open fs/open.c:1106 [inline]
 __x64_sys_open+0x7e/0xc0 fs/open.c:1106
 do_syscall_64+0x1b1/0x800 arch/x86/entry/common.c:287
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

The buggy address belongs to the object at ffff8801ac7b69c0
 which belongs to the cache names_cache of size 4096
The buggy address is located 736 bytes to the left of
 4096-byte region [ffff8801ac7b69c0, ffff8801ac7b79c0)
The buggy address belongs to the page:
page:ffffea0006b1ed80 count:1 mapcount:0 mapping:ffff8801ac7b69c0 index:0x0 compound_mapcount: 0
flags: 0x2fffc0000008100(slab|head)
raw: 02fffc0000008100 ffff8801ac7b69c0 0000000000000000 0000000100000001
raw: ffffea0006b1f7a0 ffffea0006b1eea0 ffff8801da988dc0 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8801ac7b6580: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff8801ac7b6600: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff8801ac7b6680: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
                                                       ^
 ffff8801ac7b6700: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff8801ac7b6780: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
==================================================================

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2018/04/20 15:43 upstream 87ef12027b9b cc402841 .config console log report syz C ci-upstream-kasan-gce-root
* Struck through repros no longer work on HEAD.