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KASAN: vmalloc-out-of-bounds Read in z_erofs_lz4_decompress

Status: upstream: reported C repro on 2025/02/25 19:01
Bug presence: origin:lts-only
[Documentation on labels]
Reported-by: syzbot+97e2bfc681254dbac9d6@syzkaller.appspotmail.com
First crash: 183d, last: 3h31m
▶ ▼ Bug presence (2)
Date Name Commit Repro Result
2025/06/06 linux-5.15.y (ToT) 1c700860e8bc C [report] KASAN: vmalloc-out-of-bounds Read in z_erofs_lz4_decompress
2025/06/06 upstream (ToT) e271ed52b344 C Didn't crash
▶ ▼ Similar bugs (5)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream KMSAN: uninit-value in z_erofs_lz4_decompress erofs 7 1 753d 753d 0/29 auto-obsoleted due to no activity on 2023/11/03 19:44
upstream KMSAN: uninit-value in z_erofs_lz4_decompress (3) erofs 7 C 16 567d 574d 0/29 closed as dup on 2024/03/19 10:34
upstream KMSAN: uninit-value in z_erofs_lz4_decompress (2) erofs 7 C 33 577d 610d 25/29 fixed on 2024/01/30 15:47
upstream KMSAN: kernel-infoleak in _copy_to_iter (7) net 23 C 138977 916d 1268d 22/29 fixed on 2023/02/24 13:50
upstream KMSAN: kernel-infoleak in _copy_to_iter (8) mm 23 C 21180 812d 906d 22/29 fixed on 2023/06/08 14:41
▶ ▼ Last patch testing requests (2)
Created Duration User Patch Repo Result
2025/07/05 01:41 14m retest repro linux-5.15.y report log
2025/07/05 01:41 11m retest repro linux-5.15.y report log
▶ ▼ Fix bisection attempts (1)
Created Duration User Patch Repo Result
2025/07/20 21:06 2h49m fix candidate upstream OK (0) job log

Sample crash report:
erofs: (device loop0): z_erofs_extent_lookback: bogus lookback distance @ nid 36
erofs: (device loop0): z_erofs_readahead: readahead error at page 46 @ nid 36
attempt to access beyond end of device
loop0: rw=524288, want=32, limit=16
erofs: (device loop0): z_erofs_lz4_decompress: failed to decompress -29 in[58, 4038] out[3537]
==================================================================
BUG: KASAN: vmalloc-out-of-bounds in hex_dump_to_buffer+0x3c0/0xd50 lib/hexdump.c:193
Read of size 1 at addr ffffc90000e47000 by task syz-executor301/4166

CPU: 1 PID: 4166 Comm: syz-executor301 Not tainted 5.15.185-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
Call Trace:
 <TASK>
 dump_stack_lvl+0x168/0x230 lib/dump_stack.c:106
 print_address_description+0x60/0x2d0 mm/kasan/report.c:248
 __kasan_report mm/kasan/report.c:434 [inline]
 kasan_report+0xdf/0x130 mm/kasan/report.c:451
 hex_dump_to_buffer+0x3c0/0xd50 lib/hexdump.c:193
 print_hex_dump+0x136/0x260 lib/hexdump.c:276
 z_erofs_lz4_decompress+0xc7f/0x1180 fs/erofs/decompressor.c:243
 z_erofs_decompress_generic fs/erofs/decompressor.c:332 [inline]
 z_erofs_decompress+0x767/0xde0 fs/erofs/decompressor.c:410
 z_erofs_decompress_pcluster fs/erofs/zdata.c:980 [inline]
 z_erofs_decompress_queue+0x11a6/0x1990 fs/erofs/zdata.c:1058
 z_erofs_runqueue+0x164c/0x1890 fs/erofs/zdata.c:1370
 z_erofs_readahead+0xb81/0x10c0 fs/erofs/zdata.c:1459
 read_pages+0x165/0x920 mm/readahead.c:130
 page_cache_ra_unbounded+0x830/0x930 mm/readahead.c:239
 do_page_cache_ra mm/readahead.c:269 [inline]
 force_page_cache_ra+0x3e5/0x440 mm/readahead.c:301
 force_page_cache_readahead mm/internal.h:78 [inline]
 generic_fadvise+0x520/0x7d0 mm/fadvise.c:107
 vfs_fadvise mm/fadvise.c:186 [inline]
 ksys_fadvise64_64 mm/fadvise.c:200 [inline]
 __do_sys_fadvise64 mm/fadvise.c:215 [inline]
 __se_sys_fadvise64 mm/fadvise.c:213 [inline]
 __x64_sys_fadvise64+0x139/0x180 mm/fadvise.c:213
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7fec7c8406b9
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 61 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 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffd721e6068 EFLAGS: 00000246 ORIG_RAX: 00000000000000dd
RAX: ffffffffffffffda RBX: 00007ffd721e6238 RCX: 00007fec7c8406b9
RDX: 0000000000020000 RSI: 000000000000fcff RDI: 0000000000000004
RBP: 00007fec7c8b3610 R08: 0000000000000000 R09: 00007ffd721e6238
R10: 0000000000000003 R11: 0000000000000246 R12: 0000000000000001
R13: 00007ffd721e6228 R14: 0000000000000001 R15: 0000000000000001
 </TASK>


Memory state around the buggy address:
 ffffc90000e46f00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffffc90000e46f80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffffc90000e47000: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8
                   ^
 ffffc90000e47080: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8
 ffffc90000e47100: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8
==================================================================

Crashes (484):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/06/06 01:31 linux-5.15.y 1c700860e8bc 6b6b5f21 .config console log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro (corrupt fs)] ci2-linux-5-15-kasan KASAN: vmalloc-out-of-bounds Read in z_erofs_lz4_decompress
2025/02/25 19:59 linux-5.15.y c16c81c81336 d34966d1 .config console log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro (corrupt fs)] ci2-linux-5-15-kasan-arm64 KASAN: vmalloc-out-of-bounds Read in z_erofs_lz4_decompress
2025/02/25 19:21 linux-5.15.y c16c81c81336 d34966d1 .config console log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro (corrupt fs)] ci2-linux-5-15-kasan-arm64 KASAN: vmalloc-out-of-bounds Read in z_erofs_lz4_decompress
2025/08/28 13:52 linux-5.15.y c79648372d02 e12e5ba4 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: vmalloc-out-of-bounds Read in z_erofs_lz4_decompress
2025/08/28 13:44 linux-5.15.y c79648372d02 e12e5ba4 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: vmalloc-out-of-bounds Read in z_erofs_lz4_decompress
2025/08/28 02:43 linux-5.15.y c79648372d02 e12e5ba4 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: vmalloc-out-of-bounds Read in z_erofs_lz4_decompress
2025/08/28 00:50 linux-5.15.y c79648372d02 e12e5ba4 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: vmalloc-out-of-bounds Read in z_erofs_lz4_decompress
2025/08/26 08:55 linux-5.15.y c79648372d02 bf27483f .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: vmalloc-out-of-bounds Read in z_erofs_lz4_decompress
2025/08/25 22:21 linux-5.15.y c79648372d02 bf27483f .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: vmalloc-out-of-bounds Read in z_erofs_lz4_decompress
2025/08/24 23:42 linux-5.15.y c79648372d02 bf27483f .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: vmalloc-out-of-bounds Read in z_erofs_lz4_decompress
2025/08/24 16:50 linux-5.15.y c79648372d02 bf27483f .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: vmalloc-out-of-bounds Read in z_erofs_lz4_decompress
2025/08/17 21:38 linux-5.15.y c79648372d02 1804e95e .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: vmalloc-out-of-bounds Read in z_erofs_lz4_decompress
2025/08/17 02:23 linux-5.15.y c79648372d02 1804e95e .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: vmalloc-out-of-bounds Read in z_erofs_lz4_decompress
2025/08/16 23:21 linux-5.15.y c79648372d02 1804e95e .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: vmalloc-out-of-bounds Read in z_erofs_lz4_decompress
2025/08/16 19:56 linux-5.15.y c79648372d02 1804e95e .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: vmalloc-out-of-bounds Read in z_erofs_lz4_decompress
2025/08/13 07:29 linux-5.15.y c79648372d02 22ec1469 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: vmalloc-out-of-bounds Read in z_erofs_lz4_decompress
2025/08/09 21:58 linux-5.15.y c79648372d02 32a0e5ed .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: vmalloc-out-of-bounds Read in z_erofs_lz4_decompress
2025/08/06 14:05 linux-5.15.y c79648372d02 ffe1dd46 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: vmalloc-out-of-bounds Read in z_erofs_lz4_decompress
2025/08/06 13:51 linux-5.15.y c79648372d02 ffe1dd46 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: vmalloc-out-of-bounds Read in z_erofs_lz4_decompress
2025/08/06 05:29 linux-5.15.y c79648372d02 ffe1dd46 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: vmalloc-out-of-bounds Read in z_erofs_lz4_decompress
2025/08/05 18:14 linux-5.15.y c79648372d02 37880f40 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: vmalloc-out-of-bounds Read in z_erofs_lz4_decompress
2025/08/05 08:28 linux-5.15.y c79648372d02 f5bcc8dc .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: vmalloc-out-of-bounds Read in z_erofs_lz4_decompress
2025/08/05 05:07 linux-5.15.y c79648372d02 f5bcc8dc .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: vmalloc-out-of-bounds Read in z_erofs_lz4_decompress
2025/08/04 02:17 linux-5.15.y c79648372d02 7368264b .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: vmalloc-out-of-bounds Read in z_erofs_lz4_decompress
2025/08/02 13:11 linux-5.15.y c79648372d02 7368264b .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: vmalloc-out-of-bounds Read in z_erofs_lz4_decompress
2025/07/13 15:25 linux-5.15.y 2f693b607545 3cda49cf .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: vmalloc-out-of-bounds Read in z_erofs_lz4_decompress
2025/07/07 09:38 linux-5.15.y 3dea0e7f549e 4f67c4ae .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: vmalloc-out-of-bounds Read in z_erofs_lz4_decompress
2025/08/26 14:11 linux-5.15.y c79648372d02 bf27483f .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-arm64 KASAN: vmalloc-out-of-bounds Read in z_erofs_lz4_decompress
2025/08/26 02:50 linux-5.15.y c79648372d02 bf27483f .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-arm64 KASAN: vmalloc-out-of-bounds Read in z_erofs_lz4_decompress
2025/08/25 03:02 linux-5.15.y c79648372d02 bf27483f .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-arm64 KASAN: vmalloc-out-of-bounds Read in z_erofs_lz4_decompress
2025/08/24 17:45 linux-5.15.y c79648372d02 bf27483f .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-arm64 KASAN: vmalloc-out-of-bounds Read in z_erofs_lz4_decompress
2025/08/17 22:54 linux-5.15.y c79648372d02 1804e95e .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-arm64 KASAN: vmalloc-out-of-bounds Read in z_erofs_lz4_decompress
2025/08/17 05:17 linux-5.15.y c79648372d02 1804e95e .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-arm64 KASAN: vmalloc-out-of-bounds Read in z_erofs_lz4_decompress
2025/08/14 02:55 linux-5.15.y c79648372d02 22ec1469 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-arm64 KASAN: vmalloc-out-of-bounds Read in z_erofs_lz4_decompress
2025/08/07 18:05 linux-5.15.y c79648372d02 04cffc22 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-arm64 KASAN: vmalloc-out-of-bounds Read in z_erofs_lz4_decompress
2025/08/06 10:10 linux-5.15.y c79648372d02 ffe1dd46 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-arm64 KASAN: vmalloc-out-of-bounds Read in z_erofs_lz4_decompress
2025/08/06 09:07 linux-5.15.y c79648372d02 ffe1dd46 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-arm64 KASAN: vmalloc-out-of-bounds Read in z_erofs_lz4_decompress
2025/08/05 22:16 linux-5.15.y c79648372d02 37880f40 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-arm64 KASAN: vmalloc-out-of-bounds Read in z_erofs_lz4_decompress
2025/08/05 16:19 linux-5.15.y c79648372d02 37880f40 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-arm64 KASAN: vmalloc-out-of-bounds Read in z_erofs_lz4_decompress
2025/08/05 08:32 linux-5.15.y c79648372d02 f5bcc8dc .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-arm64 KASAN: vmalloc-out-of-bounds Read in z_erofs_lz4_decompress
2025/08/05 01:49 linux-5.15.y c79648372d02 f5bcc8dc .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-arm64 KASAN: vmalloc-out-of-bounds Read in z_erofs_lz4_decompress
2025/08/04 00:37 linux-5.15.y c79648372d02 7368264b .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-arm64 KASAN: vmalloc-out-of-bounds Read in z_erofs_lz4_decompress
2025/08/03 18:12 linux-5.15.y c79648372d02 7368264b .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-arm64 KASAN: vmalloc-out-of-bounds Read in z_erofs_lz4_decompress
2025/08/03 12:25 linux-5.15.y c79648372d02 7368264b .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-arm64 KASAN: vmalloc-out-of-bounds Read in z_erofs_lz4_decompress
2025/08/02 09:16 linux-5.15.y c79648372d02 7368264b .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-arm64 KASAN: vmalloc-out-of-bounds Read in z_erofs_lz4_decompress
2025/08/02 09:16 linux-5.15.y c79648372d02 7368264b .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-arm64 KASAN: vmalloc-out-of-bounds Read in z_erofs_lz4_decompress
2025/02/25 19:01 linux-5.15.y c16c81c81336 d34966d1 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-arm64 KASAN: vmalloc-out-of-bounds Read in z_erofs_lz4_decompress
* Struck through repros no longer work on HEAD.