[v6.1] WARNING in nvmet_fc_alloc_ls_iodlist

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: e4f7d8be268e Linux 6.1.182
git tree: linux-6.1.y
console output: https://syzkaller.appspot.com/x/log.txt?x=1558c2c6580000
kernel config: https://syzkaller.appspot.com/x/.config?x=872c04466179833f
dashboard link: https://syzkaller.appspot.com/bug?extid=a6c5d4f1908190e23e73
compiler: Debian clang version 22.1.8 (++20260613092233+e80beda6e255-1~exp1~20260613092250.77), Debian LLD 22.1.8
userspace arch: arm64
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=1392bfb9580000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=12a30079580000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/7cd9b1875376/disk-e4f7d8be.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/4b5d35d18c31/vmlinux-e4f7d8be.xz
kernel image: https://storage.googleapis.com/syzbot-assets/d5ee64c2af77/Image-e4f7d8be.gz.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+a6c5d4...@syzkaller.appspotmail.com

__invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
invoke_syscall+0x98/0x290 arch/arm64/kernel/syscall.c:52
el0_svc_common+0x13c/0x258 arch/arm64/kernel/syscall.c:140
do_el0_svc+0x5c/0x134 arch/arm64/kernel/syscall.c:204
el0_svc+0x58/0x128 arch/arm64/kernel/entry-common.c:637
el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655
el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:585
------------[ cut here ]------------
WARNING: CPU: 1 PID: 4536 at mm/slab_common.c:904 free_large_kmalloc+0x30/0x158 mm/slab_common.c:905
Modules linked in:
CPU: 1 PID: 4536 Comm: syz.0.17 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/02/2026
pstate: 42400005 (nZcv daif +PAN -UAO +TCO -DIT -SSBS BTYPE=--)
pc : free_large_kmalloc+0x30/0x158 mm/slab_common.c:905
lr : kfree+0xf4/0x1a8 mm/slab_common.c:982
sp : ffff8000210577b0
x29: ffff8000210577b0 x28: dead000000000100 x27: dfff800000000000
x26: ffff0000d584ec38 x25: 0000000000000000 x24: ffff0000d584ec98
x23: ffff0000ef9a0000 x22: ffff0000ef9a0000 x21: 0000000000040000
x20: ffff0000ef99ff20 x19: fffffc0003be67c0 x18: 0000000000000000
x17: 0000000000000000 x16: ffff800011b90080 x15: 0000000000000000
x14: 0000000000000001 x13: 1ffff00002ac6fce x12: 0000000000000000
x11: ff0080000808d058 x10: dead0000000000ff x9 : dead000000000100
x8 : ffff800017d5d000 x7 : 0000000000000001 x6 : 0000000000000001
x5 : 00000000ffffffff x4 : 0000000000000dc0 x3 : 0000000000000dc0
x2 : ffff0000ef9a0010 x1 : ffff0000ef99ff20 x0 : fffffc0003be67c0
Call trace:
free_large_kmalloc+0x30/0x158 mm/slab_common.c:905
kfree+0xf4/0x1a8 mm/slab_common.c:982
nvmet_fc_alloc_ls_iodlist+0x7c4/0x7ec drivers/nvme/target/fc.c:574
nvmet_fc_register_targetport+0x5d0/0x818 drivers/nvme/target/fc.c:1413
fcloop_create_target_port+0x120/0x420 drivers/nvme/target/fcloop.c:1427
dev_attr_store+0x6c/0x90 drivers/base/core.c:2388
sysfs_kf_write+0x1f8/0x274 fs/sysfs/file.c:140
kernfs_fop_write_iter+0x390/0x4b4 fs/kernfs/file.c:352
call_write_iter include/linux/fs.h:2265 [inline]
new_sync_write fs/read_write.c:491 [inline]
vfs_write+0x3c8/0x7c8 fs/read_write.c:584
ksys_write+0x12c/0x228 fs/read_write.c:637
__do_sys_write fs/read_write.c:649 [inline]
__se_sys_write fs/read_write.c:646 [inline]
__arm64_sys_write+0x7c/0x90 fs/read_write.c:646
__invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
invoke_syscall+0x98/0x290 arch/arm64/kernel/syscall.c:52
el0_svc_common+0x13c/0x258 arch/arm64/kernel/syscall.c:140
do_el0_svc+0x5c/0x134 arch/arm64/kernel/syscall.c:204
el0_svc+0x58/0x128 arch/arm64/kernel/entry-common.c:637
el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655
el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:585
irq event stamp: 790
hardirqs last enabled at (789): [<ffff800011b8e264>] __exit_to_kernel_mode arch/arm64/kernel/entry-common.c:84 [inline]
hardirqs last enabled at (789): [<ffff800011b8e264>] exit_to_kernel_mode+0xcc/0xfc arch/arm64/kernel/entry-common.c:94
hardirqs last disabled at (790): [<ffff800011b8c2bc>] el1_dbg+0x24/0x80 arch/arm64/kernel/entry-common.c:405
softirqs last enabled at (784): [<ffff8000081ae3bc>] softirq_handle_end kernel/softirq.c:439 [inline]
softirqs last enabled at (784): [<ffff8000081ae3bc>] handle_softirqs+0xb1c/0xc90 kernel/softirq.c:624
softirqs last disabled at (731): [<ffff800008020e6c>] __do_softirq+0x14/0x20 kernel/softirq.c:630
---[ end trace 0000000000000000 ]---
object pointer: 0x00000000b337638b
==================================================================
BUG: KASAN: invalid-free in kfree+0xf4/0x1a8 mm/slab_common.c:982
Free of addr ffff0000ef99ff20 by task syz.0.17/4536

CPU: 0 PID: 4536 Comm: syz.0.17 Tainted: G W syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/02/2026
Call trace:
dump_backtrace+0x1c4/0x1f0 arch/arm64/kernel/stacktrace.c:158
show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:165
__dump_stack+0x30/0x40 lib/dump_stack.c:88
dump_stack_lvl+0xf4/0x15c lib/dump_stack.c:106
print_address_description+0x88/0x218 mm/kasan/report.c:316
print_report+0x50/0x68 mm/kasan/report.c:420
kasan_report_invalid_free+0x98/0xe4 mm/kasan/report.c:489
____kasan_kfree_large mm/kasan/common.c:-1 [inline]
__kasan_kfree_large+0xa4/0xc0 mm/kasan/common.c:273
kasan_kfree_large include/linux/kasan.h:185 [inline]
free_large_kmalloc+0x68/0x158 mm/slab_common.c:908
kfree+0xf4/0x1a8 mm/slab_common.c:982
nvmet_fc_alloc_ls_iodlist+0x7c4/0x7ec drivers/nvme/target/fc.c:574
nvmet_fc_register_targetport+0x5d0/0x818 drivers/nvme/target/fc.c:1413
fcloop_create_target_port+0x120/0x420 drivers/nvme/target/fcloop.c:1427
dev_attr_store+0x6c/0x90 drivers/base/core.c:2388
sysfs_kf_write+0x1f8/0x274 fs/sysfs/file.c:140
kernfs_fop_write_iter+0x390/0x4b4 fs/kernfs/file.c:352
call_write_iter include/linux/fs.h:2265 [inline]
new_sync_write fs/read_write.c:491 [inline]
vfs_write+0x3c8/0x7c8 fs/read_write.c:584
ksys_write+0x12c/0x228 fs/read_write.c:637
__do_sys_write fs/read_write.c:649 [inline]
__se_sys_write fs/read_write.c:646 [inline]
__arm64_sys_write+0x7c/0x90 fs/read_write.c:646
__invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
invoke_syscall+0x98/0x290 arch/arm64/kernel/syscall.c:52
el0_svc_common+0x13c/0x258 arch/arm64/kernel/syscall.c:140
do_el0_svc+0x5c/0x134 arch/arm64/kernel/syscall.c:204
el0_svc+0x58/0x128 arch/arm64/kernel/entry-common.c:637
el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655
el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:585

The buggy address belongs to the physical page:
page:00000000c0cded69 refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x12f99f
flags: 0x5ffc00000000000(node=0|zone=2|lastcpupid=0x7ff)
raw: 05ffc00000000000 dead000000000100 dead000000000122 0000000000000000
raw: 0000000000000000 0000000000000000 00000000ffffffff 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
ffff0000ef99fe00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
ffff0000ef99fe80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
>ffff0000ef99ff00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
^
ffff0000ef99ff80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
ffff0000ef9a0000: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
==================================================================
page:00000000c0cded69 refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x12f99f
flags: 0x5ffc00000000000(node=0|zone=2|lastcpupid=0x7ff)
raw: 05ffc00000000000 dead000000000100 dead000000000122 0000000000000000
raw: 0000000000000000 0000000000000000 00000000ffffffff 0000000000000000
page dumped because: VM_BUG_ON_PAGE(page_ref_count(page) == 0)
------------[ cut here ]------------
kernel BUG at include/linux/mm.h:780!
Internal error: Oops - BUG: 00000000f2000800 [#1] PREEMPT SMP
Modules linked in:
CPU: 1 PID: 4536 Comm: syz.0.17 Tainted: G B W syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/02/2026
pstate: 82400005 (Nzcv daif +PAN -UAO +TCO -DIT -SSBS BTYPE=--)
pc : put_page_testzero include/linux/mm.h:780 [inline]
pc : __free_pages+0x160/0x1cc mm/page_alloc.c:5746
lr : put_page_testzero include/linux/mm.h:780 [inline]
lr : __free_pages+0x160/0x1cc mm/page_alloc.c:5746
sp : ffff800021057770
x29: ffff800021057770 x28: dead000000000100 x27: dfff800000000000
x26: ffff0000d584ec38 x25: 0000000000000000 x24: ffff0000d584ec98
x23: dfff800000000000 x22: 05ffc00000000000 x21: fffffc0003be67f4
x20: 0000000000000000 x19: fffffc0003be67c0 x18: 1fffe00033e7697e
x17: 0000000000000000 x16: ffff800011b90080 x15: 0000000000000000
x14: 0000000000000001 x13: 1fffe00033e769a3 x12: 0000000000000000
x11: ff008000087c9780 x10: 0000000000000000 x9 : ffff8000087c9780
x8 : ffff0000d51a9c00 x7 : 0000000000000001 x6 : 0000000000000001
x5 : ffff8000210571b8 x4 : ffff800015464e80 x3 : ffff800008540904
x2 : 0000000000000001 x1 : 0000000100000000 x0 : 000000000000003e
Call trace:
put_page_testzero include/linux/mm.h:780 [inline]
__free_pages+0x160/0x1cc mm/page_alloc.c:5746
free_large_kmalloc+0xc8/0x158 mm/slab_common.c:913
kfree+0xf4/0x1a8 mm/slab_common.c:982
nvmet_fc_alloc_ls_iodlist+0x7c4/0x7ec drivers/nvme/target/fc.c:574
nvmet_fc_register_targetport+0x5d0/0x818 drivers/nvme/target/fc.c:1413
fcloop_create_target_port+0x120/0x420 drivers/nvme/target/fcloop.c:1427
dev_attr_store+0x6c/0x90 drivers/base/core.c:2388
sysfs_kf_write+0x1f8/0x274 fs/sysfs/file.c:140
kernfs_fop_write_iter+0x390/0x4b4 fs/kernfs/file.c:352
call_write_iter include/linux/fs.h:2265 [inline]
new_sync_write fs/read_write.c:491 [inline]
vfs_write+0x3c8/0x7c8 fs/read_write.c:584
ksys_write+0x12c/0x228 fs/read_write.c:637
__do_sys_write fs/read_write.c:649 [inline]
__se_sys_write fs/read_write.c:646 [inline]
__arm64_sys_write+0x7c/0x90 fs/read_write.c:646
__invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
invoke_syscall+0x98/0x290 arch/arm64/kernel/syscall.c:52
el0_svc_common+0x13c/0x258 arch/arm64/kernel/syscall.c:140
do_el0_svc+0x5c/0x134 arch/arm64/kernel/syscall.c:204
el0_svc+0x58/0x128 arch/arm64/kernel/entry-common.c:637
el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655
el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:585
Code: d004a9c1 91328021 aa1303e0 97fdfec8 (d4210000)
---[ end trace 0000000000000000 ]---


---
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