WARNING: zero-size vmalloc in disksize_store

Status: upstream: reported C repro on 2026/09/21 09:25
Reported-by: syzbot+9b3da6365d4c9f8fc8be@syzkaller.appspotmail.com
First crash: 1d01h, last: 23h40m
▶ ▼ 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 1d00h 1d02h 0/3 upstream: reported C repro on 2026/09/21 08:16
linux-6.6 WARNING: zero-size vmalloc in disksize_store -1 syz, C 3 22h24m 22h55m 0/2 upstream: reported C repro on 2026/09/21 11:39
upstream WARNING: zero-size vmalloc in disksize_store block prio:low -1 syz, C 4 1d00h 18h41m 0/29 upstream: reported C repro on 2026/09/21 15:53

Sample crash report:
------------[ cut here ]------------
WARNING: CPU: 0 PID: 4317 at mm/vmalloc.c:2994 __vmalloc_node_range+0x800/0x8b0 mm/vmalloc.c:2994
Modules linked in:
CPU: 0 PID: 4317 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+0x800/0x8b0 mm/vmalloc.c:2994
Code: 00 e8 c4 e2 ff ff 45 31 f6 e9 cd fa ff ff e8 17 12 c6 ff 45 31 f6 e9 c0 fa ff ff e8 0a 12 c6 ff e9 9a fd ff ff e8 00 12 c6 ff <0f> 0b 45 31 f6 e9 a7 fa ff ff e8 f1 11 c6 ff 48 89 df e8 d9 e0 ff
RSP: 0018:ffffc90003cefb48 EFLAGS: 00010293
RAX: ffffffff81b302a0 RBX: 0000000000000000 RCX: ffff888026511dc0
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000001 R08: 0000000000000dc0 R09: 8000000000000163
R10: dffffc0000000000 R11: ffffed100402fb06 R12: ffffc90000000000
R13: 0000000000000dc0 R14: 8000000000000163 R15: ffffe8ffffffffff
FS:  000055555a8ba500(0000) GS:ffff8880b9100000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000558831c3fc80 CR3: 000000001e706000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 __vmalloc_node mm/vmalloc.c:3087 [inline]
 vzalloc+0x75/0x80 mm/vmalloc.c:3157
 zram_meta_alloc drivers/block/zram/zram_drv.c:1166 [inline]
 disksize_store+0xf5/0x320 drivers/block/zram/zram_drv.c:1745
 kernfs_fop_write_iter+0x3a8/0x500 fs/kernfs/file.c:296
 call_write_iter include/linux/fs.h:2179 [inline]
 new_sync_write fs/read_write.c:507 [inline]
 vfs_write+0x748/0xd70 fs/read_write.c:594
 ksys_write+0x153/0x260 fs/read_write.c:647
 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: 0033:0x7fc0cc92c159
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:00007fff2e7fdb78 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007fc0ccbb3fa0 RCX: 00007fc0cc92c159
RDX: 0000000000000012 RSI: 0000200000000000 RDI: 0000000000000003
RBP: 00007fc0cc9c306b R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fc0ccbb3fac R14: 00007fc0ccbb3fa0 R15: 00007fc0ccbb3fa0
 </TASK>

Crashes (3):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/09/21 10:53 linux-5.15.y 0248c33e835e 853b104b .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan WARNING: zero-size vmalloc in disksize_store
2026/09/21 09:27 linux-5.15.y 0248c33e835e 853b104b .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan WARNING: zero-size vmalloc in disksize_store
2026/09/21 09:24 linux-5.15.y 0248c33e835e 853b104b .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan WARNING: zero-size vmalloc in disksize_store
* Struck through repros no longer work on HEAD.