KASAN: invalid-free in nvmet_fc_alloc_ls_iodlist

Status: upstream: reported syz repro on 2026/08/08 18:50
Reported-by: syzbot+d4d7b877f94b3e0458de@syzkaller.appspotmail.com
First crash: 72d, last: 72d
▶ ▼ Bug presence (1)
Date Name Commit Repro Result
2026/09/08 upstream (ToT) 28924df2a08f syz Didn't crash
▶ ▼ Similar bugs (1)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream KASAN: invalid-free in nvmet_fc_alloc_ls_iodlist nvme prio:high 24 2 66d 71d 0/29 closed as dup on 2026/08/12 16:57

Sample crash report:
 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
==================================================================
BUG: KASAN: invalid-free in slab_free mm/slub.c:3687 [inline]
BUG: KASAN: invalid-free in __kmem_cache_free+0xbc/0x21c mm/slub.c:3700
Free of addr ffff0000d9f3ff20 by task syz.0.17/4526

CPU: 0 PID: 4526 Comm: syz.0.17 Not tainted 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_slab_free+0x168/0x1b0 mm/kasan/common.c:-1
 __kasan_slab_free+0x18/0x28 mm/kasan/common.c:245
 kasan_slab_free include/linux/kasan.h:177 [inline]
 slab_free_hook mm/slub.c:1729 [inline]
 slab_free_freelist_hook+0x16c/0x1e8 mm/slub.c:1755
 slab_free mm/slub.c:3687 [inline]
 __kmem_cache_free+0xbc/0x21c mm/slub.c:3700
 kfree+0xd0/0x1a8 mm/slab_common.c:988
 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

Allocated by task 3995:
 kasan_save_stack mm/kasan/common.c:46 [inline]
 kasan_set_track+0x4c/0x80 mm/kasan/common.c:53
 kasan_save_alloc_info+0x24/0x30 mm/kasan/generic.c:505
 __kasan_slab_alloc+0x70/0x88 mm/kasan/common.c:329
 kasan_slab_alloc include/linux/kasan.h:201 [inline]
 slab_post_alloc_hook+0x74/0x430 mm/slab.h:737
 kmem_cache_alloc_bulk+0x420/0x4e8 mm/slub.c:3880
 mt_alloc_bulk lib/maple_tree.c:159 [inline]
 mas_alloc_nodes+0x3b4/0x758 lib/maple_tree.c:1301
 mas_node_count_gfp lib/maple_tree.c:1361 [inline]
 mas_expected_entries+0x1bc/0x2f0 lib/maple_tree.c:5921
 dup_mmap kernel/fork.c:619 [inline]
 dup_mm kernel/fork.c:1548 [inline]
 copy_mm+0x5a0/0x1208 kernel/fork.c:1597
 copy_process+0x1718/0x38f4 kernel/fork.c:2358
 kernel_clone+0x1ec/0x938 kernel/fork.c:2765
 __do_sys_clone kernel/fork.c:2906 [inline]
 __se_sys_clone kernel/fork.c:2874 [inline]
 __arm64_sys_clone+0x15c/0x1c8 kernel/fork.c:2874
 __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

Freed by task 3995:
 kasan_save_stack mm/kasan/common.c:46 [inline]
 kasan_set_track+0x4c/0x80 mm/kasan/common.c:53
 kasan_save_free_info+0x38/0x5c mm/kasan/generic.c:516
 ____kasan_slab_free+0x148/0x1b0 mm/kasan/common.c:237
 __kasan_slab_free+0x18/0x28 mm/kasan/common.c:245
 kasan_slab_free include/linux/kasan.h:177 [inline]
 slab_free_hook mm/slub.c:1729 [inline]
 slab_free_freelist_hook+0x16c/0x1e8 mm/slub.c:1755
 slab_free mm/slub.c:3687 [inline]
 kmem_cache_free_bulk+0x340/0x3d4 mm/slub.c:3805
 mt_free_bulk lib/maple_tree.c:164 [inline]
 mas_destroy+0x1c30/0x232c lib/maple_tree.c:5864
 dup_mmap kernel/fork.c:714 [inline]
 dup_mm kernel/fork.c:1548 [inline]
 copy_mm+0xc10/0x1208 kernel/fork.c:1597
 copy_process+0x1718/0x38f4 kernel/fork.c:2358
 kernel_clone+0x1ec/0x938 kernel/fork.c:2765
 __do_sys_clone kernel/fork.c:2906 [inline]
 __se_sys_clone kernel/fork.c:2874 [inline]
 __arm64_sys_clone+0x15c/0x1c8 kernel/fork.c:2874
 __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 object at ffff0000d9f3fe00
 which belongs to the cache maple_node of size 256
The buggy address is located 32 bytes to the right of
 256-byte region [ffff0000d9f3fe00, ffff0000d9f3ff00)

The buggy address belongs to the physical page:
page:000000009fca4206 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x119f3e
head:000000009fca4206 order:1 compound_mapcount:0 compound_pincount:0
flags: 0x5ffc00000010200(slab|head|node=0|zone=2|lastcpupid=0x7ff)
raw: 05ffc00000010200 fffffc000367cf00 dead000000000003 ffff0000c000d680
raw: 0000000000000000 0000000000100010 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff0000d9f3fe00: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff0000d9f3fe80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff0000d9f3ff00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
                               ^
 ffff0000d9f3ff80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff0000d9f40000: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
==================================================================

Crashes (2):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/08/08 19:16 linux-6.1.y e4f7d8be268e 5d63f80b .config console log report syz / log [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 KASAN: invalid-free in nvmet_fc_alloc_ls_iodlist
2026/08/08 18:49 linux-6.1.y e4f7d8be268e 5d63f80b .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 KASAN: invalid-free in nvmet_fc_alloc_ls_iodlist
* Struck through repros no longer work on HEAD.