WARNING: zero-size vmalloc in disksize_store

Status: upstream: reported C repro on 2026/09/21 15:53
Subsystems: block
Labels: prio:low
[Documentation on labels]
Reported-by: syzbot+fb23651a7efbea8868ed@syzkaller.appspotmail.com
First crash: 19h01m, last: 17h31m
▶ ▼ ✨ AI Jobs (1)
ID Workflow Result Correct Bug Created Started Finished Revision
c629ba79 assessment-security DenialOfService: ❌ Exploitable: ❌ FilesystemTrigger: ❌ NetworkTrigger: ❌ PeripheralTrigger: ❌ RemoteTrigger: ❌ Unprivileged: ❌ UserNamespace: ❌ VMGuestTrigger: ❌ VMHostTrigger: ❌ ❓ WARNING: zero-size vmalloc in disksize_store 2026/09/22 01:46 2026/09/22 01:46 2026/09/22 02:00 853b104b
▶ ▼ Discussions (1)
Title Replies (including bot) Last reply
[syzbot] [block?] WARNING: zero-size vmalloc in disksize_store 0 (1) 2026/09/21 15:53
▶ ▼ 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 17h15m 18h58m 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 16h20m 17h49m 0/3 upstream: reported C repro on 2026/09/21 09:25
linux-6.6 WARNING: zero-size vmalloc in disksize_store -1 syz, C 3 15h04m 15h35m 0/2 upstream: reported C repro on 2026/09/21 11:39

Sample crash report:
------------[ cut here ]------------
WARNING: mm/vmalloc.c:4038 at __vmalloc_node_range_noprof+0x798/0x8ec mm/vmalloc.c:4038, CPU#0: syz.2.17/3661
Modules linked in:
CPU: 0 UID: 0 PID: 3661 Comm: syz.2.17 Tainted: G        W           syzkaller #0 PREEMPT 
Tainted: [W]=WARN
Hardware name: linux,dummy-virt (DT)
pstate: 01402009 (nzcv daif +PAN -UAO -TCO +DIT -SSBS BTYPE=--)
pc : __vmalloc_node_range_noprof+0x798/0x8ec mm/vmalloc.c:4038
lr : __vmalloc_node_noprof mm/vmalloc.c:4166 [inline]
lr : vzalloc_noprof+0x94/0xa4 mm/vmalloc.c:4244
sp : ffff800089a53b20
x29: ffff800089a53b30 x28: fcf00000046e0000 x27: 00000000ffffffff
x26: 0000000000000000 x25: 0000000000000000 x24: 0000000000000000
x23: 0000000000000000 x22: f3f00000057d3140 x21: 0000000000000012
x20: 0000000000000000 x19: f3f00000057d3100 x18: 0000000000000000
x17: 0000000000000000 x16: 0000000000000000 x15: 0000000020000000
x14: 0000000000000000 x13: 0000000000000000 x12: 0000000080000000
x11: 0000000000000000 x10: 0fffffffffffffff x9 : 0000000000000010
x8 : 00000000ffffffbf x7 : 00000000ffffffff x6 : 0000000000000000
x5 : 00e8000000000403 x4 : 0000000000000dc0 x3 : ffffc1ffbf800000
x2 : 0000000000000000 x1 : 0000000000000000 x0 : 0000000000000000
Call trace:
 __vmalloc_node_range_noprof+0x798/0x8ec mm/vmalloc.c:4038 (P)
 __vmalloc_node_noprof mm/vmalloc.c:4166 [inline]
 vzalloc_noprof+0x94/0xa4 mm/vmalloc.c:4244
 zram_meta_alloc drivers/block/zram/zram_drv.c:1982 [inline]
 disksize_store+0x64/0x1b0 drivers/block/zram/zram_drv.c:2872
 dev_attr_store+0x18/0x2c drivers/base/core.c:2509
 sysfs_kf_write+0x7c/0x98 fs/sysfs/file.c:145
 kernfs_fop_write_iter+0x138/0x200 fs/kernfs/file.c:345
 new_sync_write fs/read_write.c:595 [inline]
 vfs_write+0x244/0x36c fs/read_write.c:687
 ksys_write+0x70/0x108 fs/read_write.c:739
 __do_sys_write fs/read_write.c:750 [inline]
 __se_sys_write fs/read_write.c:747 [inline]
 __arm64_sys_write+0x18/0x24 fs/read_write.c:747
 __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline]
 invoke_syscall+0x54/0x10c arch/arm64/kernel/syscall.c:49
 el0_svc_common.constprop.0+0x40/0xe0 arch/arm64/kernel/syscall.c:121
 do_el0_svc+0x1c/0x34 arch/arm64/kernel/syscall.c:140
 el0_svc+0x38/0x1fc arch/arm64/kernel/entry-common.c:758
 el0t_64_sync_handler+0xa0/0xe4 arch/arm64/kernel/entry-common.c:777
 el0t_64_sync+0x1a4/0x1a8 arch/arm64/kernel/entry.S:590
---[ end trace 0000000000000000 ]---

Crashes (4):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/09/21 09:43 https://kernel.googlesource.com/pub/scm/linux/kernel/git/torvalds/linux master 73ae59e97596 853b104b .config console log report syz / log C [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu2-arm64-mte WARNING: zero-size vmalloc in disksize_store
2026/09/21 08:58 https://kernel.googlesource.com/pub/scm/linux/kernel/git/torvalds/linux master 73ae59e97596 853b104b .config console log report syz / log C [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu2-arm64-mte WARNING: zero-size vmalloc in disksize_store
2026/09/21 08:13 https://kernel.googlesource.com/pub/scm/linux/kernel/git/torvalds/linux master 73ae59e97596 853b104b .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu2-arm64-mte WARNING: zero-size vmalloc in disksize_store
2026/09/21 08:13 https://kernel.googlesource.com/pub/scm/linux/kernel/git/torvalds/linux master 73ae59e97596 853b104b .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu2-arm64-mte WARNING: zero-size vmalloc in disksize_store
* Struck through repros no longer work on HEAD.