WARNING: zero-size vmalloc in disksize_store

Status: upstream: reported C repro on 2026/09/21 11:39
Reported-by: syzbot+e7d1c1e822c5963dffa1@syzkaller.appspotmail.com
First crash: 8h21m, last: 7h50m
▶ ▼ Similar bugs (3)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-6.1 WARNING: zero-size vmalloc in disksize_store -1 syz, C 8 10h01m 11h43m 0/3 upstream: reported C repro on 2026/09/21 08:16
linux-5.15 WARNING: zero-size vmalloc in disksize_store -1 syz, C 3 9h06m 10h34m 0/3 upstream: reported C repro on 2026/09/21 09:25
upstream WARNING: zero-size vmalloc in disksize_store block -1 syz, C 4 10h17m 4h06m 0/29 upstream: reported C repro on 2026/09/21 15:53

Sample crash report:
------------[ cut here ]------------
WARNING: CPU: 0 PID: 5934 at mm/vmalloc.c:3297 __vmalloc_node_range+0x12e8/0x1320 mm/vmalloc.c:3297
Modules linked in:
CPU: 0 PID: 5934 Comm: syz.0.17 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
RIP: 0010:__vmalloc_node_range+0x12e8/0x1320 mm/vmalloc.c:3297
Code: 00 80 23 df 48 8b 44 24 48 42 80 3c 38 00 48 8b 5c 24 58 74 08 48 89 df e8 e5 8e 0d 00 48 8b 1b e9 18 ff ff ff e8 b8 02 b5 ff <0f> 0b 31 db e9 0a ff ff ff e8 3a c1 be 08 e8 a5 02 b5 ff 0f 0b e8
RSP: 0018:ffffc900046b7a60 EFLAGS: 00010293
RAX: ffffffff81d28898 RBX: 8000000000000163 RCX: ffff888021311e00
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffc900046b7c10 R08: 0000000000000dc0 R09: 8000000000000163
R10: dffffc0000000000 R11: ffffed1028277486 R12: 0000000000000dc0
R13: 0000000000000000 R14: ffffe8ffffffffff R15: dffffc0000000000
FS:  0000555580ea7500(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fed40070050 CR3: 000000001e3c6000 CR4: 00000000003506f0
Call Trace:
 <TASK>
 __vmalloc_node mm/vmalloc.c:3435 [inline]
 vzalloc+0x79/0x90 mm/vmalloc.c:3508
 zram_meta_alloc drivers/block/zram/zram_drv.c:1258 [inline]
 disksize_store+0xfe/0x3f0 drivers/block/zram/zram_drv.c:2067
 kernfs_fop_write_iter+0x3a4/0x520 fs/kernfs/file.c:352
 call_write_iter include/linux/fs.h:2018 [inline]
 new_sync_write fs/read_write.c:491 [inline]
 vfs_write+0x474/0x9a0 fs/read_write.c:584
 ksys_write+0x151/0x260 fs/read_write.c:637
 do_syscall_x64 arch/x86/entry/common.c:46 [inline]
 do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:76
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7fed4019e159
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 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 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffef54a42a8 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007fed40425fa0 RCX: 00007fed4019e159
RDX: 0000000000000012 RSI: 0000200000000000 RDI: 0000000000000003
RBP: 00007fed4023506b R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fed40425fac R14: 00007fed40425fa0 R15: 00007fed40425fa0
 </TASK>

Crashes (3):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/09/21 12:10 linux-6.6.y 79643295eba1 853b104b .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan WARNING: zero-size vmalloc in disksize_store
2026/09/21 11:41 linux-6.6.y 79643295eba1 853b104b .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan WARNING: zero-size vmalloc in disksize_store
2026/09/21 11:38 linux-6.6.y 79643295eba1 853b104b .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan WARNING: zero-size vmalloc in disksize_store
* Struck through repros no longer work on HEAD.