Re: [syzbot] [mm?] [f2fs?] [exfat?] memory leak in __kfree_rcu_sheaf

syzbot
2026-03-08T12:47:58Z

Hello,

syzbot has tested the proposed patch but the reproducer is still triggering an issue:
memory leak in __pcs_replace_empty_main

BUG: memory leak
unreferenced object 0xffff88810005f800 (size 512):
comm "swapper/0", pid 0, jiffies 4294937296
hex dump (first 32 bytes):
00 2a 90 00 81 88 ff ff 00 94 30 29 81 88 ff ff .*........0)....
00 12 04 00 81 88 ff ff 00 00 00 00 00 00 00 00 ................
backtrace (crc a3e5799):
kmemleak_alloc_recursive include/linux/kmemleak.h:44 [inline]
slab_post_alloc_hook mm/slub.c:4547 [inline]
slab_alloc_node mm/slub.c:4869 [inline]
__do_kmalloc_node mm/slub.c:5262 [inline]
__kmalloc_noprof+0x3bd/0x560 mm/slub.c:5275
kmalloc_noprof include/linux/slab.h:954 [inline]
kzalloc_noprof include/linux/slab.h:1188 [inline]
__alloc_empty_sheaf+0x35/0x50 mm/slub.c:2771
alloc_empty_sheaf mm/slub.c:2786 [inline]
alloc_full_sheaf mm/slub.c:2834 [inline]
__pcs_replace_empty_main+0x1d2/0x260 mm/slub.c:4629
alloc_from_pcs mm/slub.c:4720 [inline]
slab_alloc_node mm/slub.c:4854 [inline]
__kmalloc_cache_noprof+0x3ac/0x480 mm/slub.c:5378
kmalloc_noprof include/linux/slab.h:950 [inline]
kzalloc_noprof include/linux/slab.h:1188 [inline]
__irq_domain_alloc_fwnode+0x37/0x140 kernel/irq/irqdomain.c:95
irq_domain_alloc_named_fwnode include/linux/irqdomain.h:271 [inline]
arch_early_irq_init+0x1c/0x70 arch/x86/kernel/apic/vector.c:803
start_kernel+0x931/0xb80 init/main.c:1114
x86_64_start_reservations+0x24/0x30 arch/x86/kernel/head64.c:310
x86_64_start_kernel+0xce/0xd0 arch/x86/kernel/head64.c:291
common_startup_64+0x13e/0x148

BUG: memory leak
unreferenced object 0xffff8881008f6c00 (size 512):
comm "kthreadd", pid 2, jiffies 4294937344
hex dump (first 32 bytes):
00 94 30 29 81 88 ff ff 00 d6 de 0b 81 88 ff ff ..0)............
00 12 04 00 81 88 ff ff 00 00 00 00 00 00 00 00 ................
backtrace (crc 9181eca5):
kmemleak_alloc_recursive include/linux/kmemleak.h:44 [inline]
slab_post_alloc_hook mm/slub.c:4547 [inline]
slab_alloc_node mm/slub.c:4869 [inline]
__do_kmalloc_node mm/slub.c:5262 [inline]
__kmalloc_noprof+0x3bd/0x560 mm/slub.c:5275
kmalloc_noprof include/linux/slab.h:954 [inline]
kzalloc_noprof include/linux/slab.h:1188 [inline]
__alloc_empty_sheaf+0x35/0x50 mm/slub.c:2771
alloc_empty_sheaf mm/slub.c:2786 [inline]
alloc_full_sheaf mm/slub.c:2834 [inline]
__pcs_replace_empty_main+0x1d2/0x260 mm/slub.c:4629
alloc_from_pcs mm/slub.c:4720 [inline]
slab_alloc_node mm/slub.c:4854 [inline]
__kmalloc_cache_node_noprof+0x3ef/0x4e0 mm/slub.c:5391
kmalloc_node_noprof include/linux/slab.h:1077 [inline]
__get_vm_area_node+0xc6/0x1d0 mm/vmalloc.c:3221
__vmalloc_node_range_noprof+0x1d3/0xe50 mm/vmalloc.c:4024
__vmalloc_node_noprof+0x71/0x90 mm/vmalloc.c:4124
alloc_thread_stack_node kernel/fork.c:355 [inline]
dup_task_struct kernel/fork.c:924 [inline]
copy_process+0x3e5/0x28c0 kernel/fork.c:2050
kernel_clone+0xac/0x6e0 kernel/fork.c:2654
kernel_thread+0x80/0xb0 kernel/fork.c:2715
create_kthread kernel/kthread.c:459 [inline]
kthreadd+0x186/0x250 kernel/kthread.c:817
ret_from_fork+0x23c/0x4b0 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

BUG: memory leak
unreferenced object 0xffff8881008fd600 (size 512):
comm "kworker/u8:6", pid 223, jiffies 4294937434
hex dump (first 32 bytes):
00 c6 8f 00 81 88 ff ff d8 2c 04 00 81 88 ff ff .........,......
00 12 04 00 81 88 ff ff 00 00 00 00 00 00 00 00 ................
backtrace (crc 33698a2f):
kmemleak_alloc_recursive include/linux/kmemleak.h:44 [inline]
slab_post_alloc_hook mm/slub.c:4547 [inline]
slab_alloc_node mm/slub.c:4869 [inline]
__do_kmalloc_node mm/slub.c:5262 [inline]
__kmalloc_noprof+0x3bd/0x560 mm/slub.c:5275
kmalloc_noprof include/linux/slab.h:954 [inline]
kzalloc_noprof include/linux/slab.h:1188 [inline]
__alloc_empty_sheaf+0x35/0x50 mm/slub.c:2771
alloc_empty_sheaf mm/slub.c:2786 [inline]
__pcs_replace_full_main+0xe8/0x300 mm/slub.c:5725
free_to_pcs mm/slub.c:5778 [inline]
slab_free mm/slub.c:6173 [inline]
kfree+0x352/0x390 mm/slub.c:6486
call_usermodehelper_freeinfo kernel/umh.c:43 [inline]
umh_complete kernel/umh.c:57 [inline]
call_usermodehelper_exec_async+0x1c7/0x1f0 kernel/umh.c:119
ret_from_fork+0x23c/0x4b0 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

BUG: memory leak
unreferenced object 0xffff8881008fc600 (size 512):
comm "kworker/0:1", pid 10, jiffies 4294937441
hex dump (first 32 bytes):
00 1a 39 10 81 88 ff ff 00 d6 8f 00 81 88 ff ff ..9.............
00 12 04 00 81 88 ff ff 00 00 00 00 00 00 00 00 ................
backtrace (crc fca1c70a):
kmemleak_alloc_recursive include/linux/kmemleak.h:44 [inline]
slab_post_alloc_hook mm/slub.c:4547 [inline]
slab_alloc_node mm/slub.c:4869 [inline]
__do_kmalloc_node mm/slub.c:5262 [inline]
__kmalloc_noprof+0x3bd/0x560 mm/slub.c:5275
kmalloc_noprof include/linux/slab.h:954 [inline]
kzalloc_noprof include/linux/slab.h:1188 [inline]
__alloc_empty_sheaf+0x35/0x50 mm/slub.c:2771
alloc_empty_sheaf mm/slub.c:2786 [inline]
__pcs_replace_full_main+0xe8/0x300 mm/slub.c:5725
free_to_pcs mm/slub.c:5778 [inline]
slab_free mm/slub.c:6173 [inline]
kfree+0x352/0x390 mm/slub.c:6486
vfree.part.0+0x1d5/0x4d0 mm/vmalloc.c:3485
vfree mm/vmalloc.c:3456 [inline]
delayed_vfree_work+0x5b/0x90 mm/vmalloc.c:3398
process_one_work+0x26c/0x5d0 kernel/workqueue.c:3275
process_scheduled_works kernel/workqueue.c:3358 [inline]
worker_thread+0x243/0x490 kernel/workqueue.c:3439
kthread+0x14e/0x1a0 kernel/kthread.c:436
ret_from_fork+0x23c/0x4b0 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

BUG: memory leak
unreferenced object 0xffff888100902a00 (size 512):
comm "kworker/0:1", pid 10, jiffies 4294937448
hex dump (first 32 bytes):
00 c4 58 09 81 88 ff ff 00 f8 05 00 81 88 ff ff ..X.............
00 12 04 00 81 88 ff ff 00 00 00 00 00 00 00 00 ................
backtrace (crc 8a5f0c0d):
kmemleak_alloc_recursive include/linux/kmemleak.h:44 [inline]
slab_post_alloc_hook mm/slub.c:4547 [inline]
slab_alloc_node mm/slub.c:4869 [inline]
__do_kmalloc_node mm/slub.c:5262 [inline]
__kmalloc_noprof+0x3bd/0x560 mm/slub.c:5275
kmalloc_noprof include/linux/slab.h:954 [inline]
kzalloc_noprof include/linux/slab.h:1188 [inline]
__alloc_empty_sheaf+0x35/0x50 mm/slub.c:2771
alloc_empty_sheaf mm/slub.c:2786 [inline]
__pcs_replace_full_main+0xe8/0x300 mm/slub.c:5725
free_to_pcs mm/slub.c:5778 [inline]
slab_free mm/slub.c:6173 [inline]
kfree+0x352/0x390 mm/slub.c:6486
vfree.part.0+0x1d5/0x4d0 mm/vmalloc.c:3485
vfree mm/vmalloc.c:3456 [inline]
delayed_vfree_work+0x5b/0x90 mm/vmalloc.c:3398
process_one_work+0x26c/0x5d0 kernel/workqueue.c:3275
process_scheduled_works kernel/workqueue.c:3358 [inline]
worker_thread+0x243/0x490 kernel/workqueue.c:3439
kthread+0x14e/0x1a0 kernel/kthread.c:436
ret_from_fork+0x23c/0x4b0 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

BUG: memory leak
unreferenced object 0xffff88810958c400 (size 512):
comm "kworker/u8:5", pid 4599, jiffies 4294937964
hex dump (first 32 bytes):
00 4c 6a 12 81 88 ff ff 00 2a 90 00 81 88 ff ff .Lj......*......
00 12 04 00 81 88 ff ff 00 00 00 00 00 00 00 00 ................
backtrace (crc 45e572cd):
kmemleak_alloc_recursive include/linux/kmemleak.h:44 [inline]
slab_post_alloc_hook mm/slub.c:4547 [inline]
slab_alloc_node mm/slub.c:4869 [inline]
__do_kmalloc_node mm/slub.c:5262 [inline]
__kmalloc_noprof+0x3bd/0x560 mm/slub.c:5275
kmalloc_noprof include/linux/slab.h:954 [inline]
kzalloc_noprof include/linux/slab.h:1188 [inline]
__alloc_empty_sheaf+0x35/0x50 mm/slub.c:2771
alloc_empty_sheaf mm/slub.c:2786 [inline]
__pcs_replace_full_main+0xe8/0x300 mm/slub.c:5725
free_to_pcs mm/slub.c:5778 [inline]
slab_free mm/slub.c:6173 [inline]
kfree+0x352/0x390 mm/slub.c:6486
call_usermodehelper_freeinfo kernel/umh.c:43 [inline]
umh_complete kernel/umh.c:57 [inline]
call_usermodehelper_exec_async+0x1c7/0x1f0 kernel/umh.c:119
ret_from_fork+0x23c/0x4b0 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

connection error: failed to recv *flatrpc.ExecutorMessageRawT: EOF

Tested on:

commit: c23719ab Merge tag 'x86-urgent-2026-03-08' of git://gi..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=10027054580000
kernel config: https://syzkaller.appspot.com/x/.config?x=2c6ad6fefffa76b1
dashboard link: https://syzkaller.appspot.com/bug?extid=cae7809e9dc1459e4e63
compiler: gcc (Debian 14.2.0-19) 14.2.0, GNU ld (GNU Binutils for Debian) 2.44
patch: https://syzkaller.appspot.com/x/patch.diff?x=17682a02580000