WARNING in generic_access_phys

Status: upstream: reported C repro on 2026/08/30 15:03
Subsystems: kernfs
Labels: prio:low
[Documentation on labels]
Reported-by: syzbot+fafc2cbca26ad7368aae@syzkaller.appspotmail.com
First crash: 1d10h, last: 2h50m
✨ AI Jobs (1)
ID Workflow Result Correct Bug Created Started Finished Revision
68e3452c assessment-security DenialOfService: ❌ Exploitable: ❌ FilesystemTrigger: ❌ NetworkTrigger: ❌ PeripheralTrigger: ❌ RemoteTrigger: ❌ Unprivileged: ❌ UserNamespace: ❌ VMGuestTrigger: ❌ VMHostTrigger: ❌ WARNING in generic_access_phys 2026/08/31 00:36 2026/08/31 00:36 2026/08/31 01:00 2f52988a
Discussions (1)
Title Replies (including bot) Last reply
[syzbot] [kernfs?] WARNING in generic_access_phys 0 (1) 2026/08/30 15:03

Sample crash report:
------------[ cut here ]------------
WARNING: ./arch/arm64/include/asm/io.h:283 at rcu_read_unlock include/linux/rcupdate.h:878 [inline], CPU#0: syz.2.18/3677
WARNING: ./arch/arm64/include/asm/io.h:283 at pte_unmap include/linux/pgtable.h:117 [inline], CPU#0: syz.2.18/3677
WARNING: ./arch/arm64/include/asm/io.h:283 at follow_pfnmap_end mm/memory.c:7077 [inline], CPU#0: syz.2.18/3677
WARNING: ./arch/arm64/include/asm/io.h:283 at generic_access_phys+0x26c/0x344 mm/memory.c:7126, CPU#0: syz.2.18/3677
Modules linked in:
CPU: 0 UID: 0 PID: 3677 Comm: syz.2.18 Tainted: G        W           syzkaller #0 PREEMPT 
Tainted: [W]=WARN
Hardware name: linux,dummy-virt (DT)
pstate: 20000005 (nzCv daif -PAN -UAO -TCO -DIT -SSBS BTYPE=--)
pc : ioremap_prot arch/arm64/include/asm/io.h:283 [inline]
pc : generic_access_phys+0x26c/0x344 mm/memory.c:7116
lr : rcu_read_unlock include/linux/rcupdate.h:882 [inline]
lr : pte_unmap include/linux/pgtable.h:117 [inline]
lr : follow_pfnmap_end mm/memory.c:7077 [inline]
lr : generic_access_phys+0xcc/0x344 mm/memory.c:7111
sp : ffff8000a2197830
x29: ffff8000a21978f0 x28: ffff8000a2197870 x27: 0000000000000000
x26: 0000000000000001 x25: ffff700010ef8fd0 x24: 0000000000001000
x23: ffff8000877c7e80 x22: 0000000000000000 x21: 0160000000000f92
x20: ffff0000127a3c80 x19: 0000000010042000 x18: 0000000000000000
x17: ffff800080c267fc x16: ffff800080e49be0 x15: ffff800080e496d8
x14: ffff800080a8ead0 x13: ffff800089e66530 x12: ffff60000325ffd5
x11: 1fffe0000325ffd4 x10: ffff60000325ffd4 x9 : dfff800000000000
x8 : ffff0000192ffea0 x7 : 0000000000000001 x6 : ffff60000325ffd4
x5 : ffff0000192ffea0 x4 : 0000000000000000 x3 : 1fffe00002a63090
x2 : 0000000000000000 x1 : 0000000000001000 x0 : 000000003fffffff
Call trace:
 rcu_read_unlock include/linux/rcupdate.h:878 [inline] (P)
 pte_unmap include/linux/pgtable.h:117 [inline] (P)
 follow_pfnmap_end mm/memory.c:7077 [inline] (P)
 generic_access_phys+0x26c/0x344 mm/memory.c:7126 (P)
 kernfs_vma_access+0x14c/0x1f0 fs/kernfs/file.c:437
 __access_remote_vm+0x3dc/0x600 mm/memory.c:7194
 access_remote_vm+0x10/0x20 mm/memory.c:7241
 mem_rw+0x16c/0x580 fs/proc/base.c:912
 mem_read+0x14/0x20 fs/proc/base.c:940
 vfs_read+0x190/0xa18 fs/read_write.c:572
 ksys_read+0xf0/0x1e0 fs/read_write.c:716
 __do_sys_read fs/read_write.c:725 [inline]
 __se_sys_read fs/read_write.c:723 [inline]
 __arm64_sys_read+0x70/0xa0 fs/read_write.c:723
 __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_compat+0x40/0x58 arch/arm64/kernel/syscall.c:146
 el0_svc_compat+0x54/0x264 arch/arm64/kernel/entry-common.c:909
 el0t_32_sync_handler+0x88/0xac arch/arm64/kernel/entry-common.c:927
 el0t_32_sync+0x19c/0x1a0 arch/arm64/kernel/entry.S:595
irq event stamp: 2632
hardirqs last  enabled at (2631): [<ffff8000859d52ec>] __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:210 [inline]
hardirqs last  enabled at (2631): [<ffff8000859d52ec>] _raw_spin_unlock_irqrestore+0x80/0xb4 kernel/locking/spinlock.c:221
hardirqs last disabled at (2632): [<ffff8000859a81d0>] el1_brk64+0x20/0x54 arch/arm64/kernel/entry-common.c:445
softirqs last  enabled at (2592): [<ffff80008007ad70>] put_cpu_fpsimd_context arch/arm64/kernel/fpsimd.c:250 [inline]
softirqs last  enabled at (2592): [<ffff80008007ad70>] fpsimd_restore_current_state+0x44/0x854 arch/arm64/kernel/fpsimd.c:1797
softirqs last disabled at (2590): [<ffff80008007b050>] fpsimd_restore_current_state+0x324/0x854 arch/arm64/kernel/fpsimd.c:1794
---[ end trace 0000000000000000 ]---

Crashes (14):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/08/30 22:38 https://kernel.googlesource.com/pub/scm/linux/kernel/git/torvalds/linux master 45c13f3f9e3b 2f52988a .config console log report syz / log C [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu2-arm64-compat WARNING in generic_access_phys
2026/08/30 19:27 https://kernel.googlesource.com/pub/scm/linux/kernel/git/torvalds/linux master 45c13f3f9e3b 2f52988a .config console log report syz / log C [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu2-arm64-compat WARNING in generic_access_phys
2026/08/30 16:28 https://kernel.googlesource.com/pub/scm/linux/kernel/git/torvalds/linux master 45c13f3f9e3b 2f52988a .config console log report syz / log C [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu2-arm64-compat WARNING in generic_access_phys
2026/08/30 12:58 https://kernel.googlesource.com/pub/scm/linux/kernel/git/torvalds/linux master 45c13f3f9e3b 2f52988a .config console log report syz / log C [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu2-arm64-compat WARNING in generic_access_phys
2026/08/31 02:01 https://kernel.googlesource.com/pub/scm/linux/kernel/git/torvalds/linux master 45c13f3f9e3b 2f52988a .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu2-arm64-compat WARNING in generic_access_phys
2026/08/31 02:00 https://kernel.googlesource.com/pub/scm/linux/kernel/git/torvalds/linux master 45c13f3f9e3b 2f52988a .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu2-arm64-compat WARNING in generic_access_phys
2026/08/30 20:45 https://kernel.googlesource.com/pub/scm/linux/kernel/git/torvalds/linux master 45c13f3f9e3b 2f52988a .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu2-arm64-compat WARNING in generic_access_phys
2026/08/30 20:39 https://kernel.googlesource.com/pub/scm/linux/kernel/git/torvalds/linux master 45c13f3f9e3b 2f52988a .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu2-arm64-compat WARNING in generic_access_phys
2026/08/29 21:10 https://kernel.googlesource.com/pub/scm/linux/kernel/git/torvalds/linux master 45c13f3f9e3b 2f52988a .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu2-arm64-compat WARNING in generic_access_phys
2026/08/29 21:09 https://kernel.googlesource.com/pub/scm/linux/kernel/git/torvalds/linux master 45c13f3f9e3b 2f52988a .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu2-arm64-compat WARNING in generic_access_phys
2026/08/29 18:14 https://kernel.googlesource.com/pub/scm/linux/kernel/git/torvalds/linux master 45c13f3f9e3b 2f52988a .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu2-arm64-compat WARNING in generic_access_phys
2026/08/29 18:13 https://kernel.googlesource.com/pub/scm/linux/kernel/git/torvalds/linux master 45c13f3f9e3b 2f52988a .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu2-arm64-compat WARNING in generic_access_phys
2026/08/29 17:59 https://kernel.googlesource.com/pub/scm/linux/kernel/git/torvalds/linux master 45c13f3f9e3b 2f52988a .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu2-arm64-compat WARNING in generic_access_phys
2026/08/29 17:58 https://kernel.googlesource.com/pub/scm/linux/kernel/git/torvalds/linux master 45c13f3f9e3b 2f52988a .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu2-arm64-compat WARNING in generic_access_phys
* Struck through repros no longer work on HEAD.