WARNING in add_mtd_device

Status: upstream: reported C repro on 2026/06/20 08:22
Subsystems: mtd
Labels: prio:low
[Documentation on labels]
Reported-by: syzbot+3ae80219c633aca5431c@syzkaller.appspotmail.com
Fix commit: ae9d8058f132 mtd: mtdpart: fix uninitialized erasesize on MTDPART_OFS_RETAIN error path a74e31d0a2d5 mtd: mtdpart: validate partition bounds in mtd_add_partition()
Patched on: [ci-qemu-gce-upstream-auto ci-qemu-upstream ci-qemu-upstream-386 ci-qemu2-arm32 ci-qemu2-arm64 ci-qemu2-arm64-compat ci-qemu2-arm64-mte ci-qemu2-riscv64 ci-snapshot-upstream-root ci-upstream-bpf-kasan-gce ci-upstream-bpf-next-kasan-gce ci-upstream-gce-arm64 ci-upstream-gce-leak ci-upstream-kasan-badwrites-root ci-upstream-kasan-gce ci-upstream-kasan-gce-386 ci-upstream-kasan-gce-root ci-upstream-kasan-gce-selinux-root ci-upstream-kasan-gce-smack-root ci-upstream-kmsan-gce-386-root ci-upstream-kmsan-gce-root ci-upstream-linux-next-kasan-gce-root ci-upstream-net-kasan-gce ci-upstream-net-this-kasan-gce ci-upstream-rust-kasan-gce ci2-upstream-fs ci2-upstream-kcsan-gce ci2-upstream-usb], missing on: [ci-qemu-native-arm64-kvm]
First crash: 52d, last: 21d
✨ AI Jobs (6)
ID Workflow Result Correct Bug Created Started Finished Revision
23ba81bc assessment-security DenialOfService: ❌ Exploitable: ❌ FilesystemTrigger: ❌ NetworkTrigger: ❌ PeripheralTrigger: ❌ RemoteTrigger: ❌ Unprivileged: ❌ UserNamespace: ❌ VMGuestTrigger: ❌ VMHostTrigger: ❌ WARNING in add_mtd_device 2026/07/22 00:00 2026/07/22 00:00 2026/07/22 00:39 0d5a7c31
4ff3b9c8 assessment-security 💥 WARNING in add_mtd_device 2026/07/05 02:16 2026/07/05 02:16 2026/07/05 02:33 93f57954
2546f8ff assessment-security 💥 WARNING in add_mtd_device 2026/06/27 00:42 2026/06/27 00:42 2026/06/27 00:54 7ff32d8b
151631d4 assessment-security 💥 WARNING in add_mtd_device 2026/06/23 00:01 2026/06/23 00:01 2026/06/23 00:24 5a630be6
83edb5b2 assessment-security 💥 WARNING in add_mtd_device 2026/06/20 00:04 2026/06/20 00:04 2026/06/20 00:04 023e42b5
04b80831 assessment-security 💥 WARNING in add_mtd_device 2026/06/18 02:07 2026/06/18 02:07 2026/06/18 02:07 b62b3ded
Discussions (3)
Title Replies (including bot) Last reply
[PATCH] mtd: mtdpart: validate partition bounds in mtd_add_partition() 2 (2) 2026/06/29 14:44
[PATCH] mtd: mtdpart: fix uninitialized erasesize on MTDPART_OFS_RETAIN error path 2 (2) 2026/06/29 14:44
[syzbot] [mtd?] WARNING in add_mtd_device 0 (4) 2026/06/20 16:09
Last patch testing requests (2)
Created Duration User Patch Repo Result
2026/06/20 16:09 51m nivchenko.dev@gmail.com patch upstream OK log
2026/06/20 13:05 47m kartikey406@gmail.com patch upstream OK log

Sample crash report:
mtd partition "" doesn't have enough space: 0x8000003 < 0x8000084bb, disabled
------------[ cut here ]------------
WARNING: drivers/mtd/mtdcore.c:719 at add_mtd_device+0x56c/0x14cc drivers/mtd/mtdcore.c:719, CPU#0: syz.2.17/3665
Modules linked in:
CPU: 0 UID: 0 PID: 3665 Comm: syz.2.17 Not tainted syzkaller #0 PREEMPT 
Hardware name: linux,dummy-virt (DT)
pstate: 10000005 (nzcV daif -PAN -UAO -TCO -DIT -SSBS BTYPE=--)
pc : add_mtd_device+0x56c/0x14cc drivers/mtd/mtdcore.c:719
lr : mtd_add_partition+0x218/0x48c drivers/mtd/mtdpart.c:280
sp : ffff8000a2c276f0
x29: ffff8000a2c277b0 x28: ffff0000158a8000 x27: ffff00001ef34004
x26: 1fffe00003de683f x25: ffff00001ef34014 x24: 0000000000000004
x23: ffff00001ef34000 x22: 1ffff00014584f02 x21: 0000000000000000
x20: ffff00001ef341a0 x19: 0000000000000c00 x18: 0000000000000000
x17: 0000000000000000 x16: 0000000000000000 x15: ffff80008764b708
x14: 1ffff00010ec96e1 x13: 0000000000000004 x12: ffff700014584ee9
x11: 1ffff00014584ee8 x10: ffff700014584ee8 x9 : dfff800000000000
x8 : ffff8000a2c27747 x7 : 1ffff00014584eea x6 : 0000000041b58ab3
x5 : ffff700014584eea x4 : ffff8000a2c27750 x3 : 1fffe00003de6800
x2 : 0000000000000000 x1 : 0000000000000007 x0 : 0000000000000000
Call trace:
 add_mtd_device+0x56c/0x14cc drivers/mtd/mtdcore.c:719 (P)
 mtd_add_partition+0x218/0x48c drivers/mtd/mtdpart.c:280
 mtdchar_blkpg_ioctl+0x17c/0x1b8 drivers/mtd/mtdchar.c:562
 mtdchar_ioctl+0x2f8/0x1ed8 drivers/mtd/mtdchar.c:1218
 mtdchar_unlocked_ioctl+0xa0/0xfc drivers/mtd/mtdchar.c:1241
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:597 [inline]
 __se_sys_ioctl fs/ioctl.c:583 [inline]
 __arm64_sys_ioctl+0x124/0x1a4 fs/ioctl.c:583
 __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline]
 invoke_syscall+0x74/0x240 arch/arm64/kernel/syscall.c:49
 el0_svc_common.constprop.0+0xac/0x230 arch/arm64/kernel/syscall.c:121
 do_el0_svc+0x40/0x58 arch/arm64/kernel/syscall.c:140
 el0_svc+0x58/0x2a4 arch/arm64/kernel/entry-common.c:736
 el0t_64_sync_handler+0xa0/0xe4 arch/arm64/kernel/entry-common.c:755
 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:594
irq event stamp: 0
hardirqs last  enabled at (0): [<0000000000000000>] 0x0
hardirqs last disabled at (0): [<ffff800080215cc8>] copy_process+0x16a8/0x5700 kernel/fork.c:2232
softirqs last  enabled at (0): [<ffff800080215ce8>] copy_process+0x16c8/0x5700 kernel/fork.c:2233
softirqs last disabled at (0): [<0000000000000000>] 0x0
---[ end trace 0000000000000000 ]---

Crashes (14):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/06/20 09:10 https://kernel.googlesource.com/pub/scm/linux/kernel/git/torvalds/linux master a975094bf98c 43bfcdb0 .config console log report syz / log C [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu2-arm64 WARNING in add_mtd_device
2026/07/17 17:42 https://kernel.googlesource.com/pub/scm/linux/kernel/git/torvalds/linux master fce2dfa773ce 7f27c57a .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu2-arm64-mte WARNING in add_mtd_device
2026/07/17 17:42 https://kernel.googlesource.com/pub/scm/linux/kernel/git/torvalds/linux master fce2dfa773ce 7f27c57a .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu2-arm64-mte WARNING in add_mtd_device
2026/07/16 16:51 https://kernel.googlesource.com/pub/scm/linux/kernel/git/torvalds/linux master 37e2f878a7a6 851bd571 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu2-arm64-mte WARNING in add_mtd_device
2026/07/16 16:51 https://kernel.googlesource.com/pub/scm/linux/kernel/git/torvalds/linux master 37e2f878a7a6 851bd571 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu2-arm64-mte WARNING in add_mtd_device
2026/07/15 15:44 https://kernel.googlesource.com/pub/scm/linux/kernel/git/torvalds/linux master 58717b2a1365 a4ed0f4f .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu2-arm64-mte WARNING in add_mtd_device
2026/07/15 06:54 https://kernel.googlesource.com/pub/scm/linux/kernel/git/torvalds/linux master 58717b2a1365 2130f682 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu2-arm64-mte WARNING in add_mtd_device
2026/07/15 06:54 https://kernel.googlesource.com/pub/scm/linux/kernel/git/torvalds/linux master 58717b2a1365 2130f682 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu2-arm64-mte WARNING in add_mtd_device
2026/07/15 06:50 https://kernel.googlesource.com/pub/scm/linux/kernel/git/torvalds/linux master 58717b2a1365 2130f682 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu2-arm64-mte WARNING in add_mtd_device
2026/07/15 06:49 https://kernel.googlesource.com/pub/scm/linux/kernel/git/torvalds/linux master 58717b2a1365 2130f682 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu2-arm64-mte WARNING in add_mtd_device
2026/06/20 05:14 https://kernel.googlesource.com/pub/scm/linux/kernel/git/torvalds/linux master a975094bf98c 43bfcdb0 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu2-arm64 WARNING in add_mtd_device
2026/06/20 05:13 https://kernel.googlesource.com/pub/scm/linux/kernel/git/torvalds/linux master a975094bf98c 43bfcdb0 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu2-arm64 WARNING in add_mtd_device
2026/06/16 08:19 https://kernel.googlesource.com/pub/scm/linux/kernel/git/torvalds/linux master 0e0611827f33 50bb0618 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu2-arm64-compat WARNING in add_mtd_device
2026/06/16 08:19 https://kernel.googlesource.com/pub/scm/linux/kernel/git/torvalds/linux master 0e0611827f33 50bb0618 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu2-arm64-compat WARNING in add_mtd_device
* Struck through repros no longer work on HEAD.