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

syzbot
2026-03-11T11:03:10Z

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):
18 ca 17 2e 81 88 ff ff 00 b6 ad 81 ff ff ff ff ................
00 12 04 00 81 88 ff ff 3c 00 00 00 00 00 00 00 ........<.......
backtrace (crc 9b7d1e76):
kmemleak_alloc_recursive include/linux/kmemleak.h:44 [inline]
slab_post_alloc_hook mm/slub.c:4550 [inline]
slab_alloc_node mm/slub.c:4873 [inline]
__do_kmalloc_node mm/slub.c:5266 [inline]
__kmalloc_noprof+0x3bd/0x560 mm/slub.c:5279
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:2836 [inline]
__pcs_replace_empty_main+0x1e0/0x2f0 mm/slub.c:4633
alloc_from_pcs mm/slub.c:4724 [inline]
slab_alloc_node mm/slub.c:4858 [inline]
__kmalloc_cache_noprof+0x3ac/0x480 mm/slub.c:5382
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):
08 5e e1 28 81 88 ff ff 00 b6 ad 81 ff ff ff ff .^.(............
00 12 04 00 81 88 ff ff 3c 00 00 00 00 00 00 00 ........<.......
backtrace (crc 89324f2):
kmemleak_alloc_recursive include/linux/kmemleak.h:44 [inline]
slab_post_alloc_hook mm/slub.c:4550 [inline]
slab_alloc_node mm/slub.c:4873 [inline]
__do_kmalloc_node mm/slub.c:5266 [inline]
__kmalloc_noprof+0x3bd/0x560 mm/slub.c:5279
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:2836 [inline]
__pcs_replace_empty_main+0x1e0/0x2f0 mm/slub.c:4633
alloc_from_pcs mm/slub.c:4724 [inline]
slab_alloc_node mm/slub.c:4858 [inline]
__kmalloc_cache_node_noprof+0x3ef/0x4e0 mm/slub.c:5395
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 0xffff8881023c6800 (size 512):
comm "kworker/u8:3", pid 829, jiffies 4294937473
hex dump (first 32 bytes):
00 56 0a 2b 81 88 ff ff 00 fe 03 2b 81 88 ff ff .V.+.......+....
00 12 04 00 81 88 ff ff 3c 00 00 00 00 00 00 00 ........<.......
backtrace (crc 175b82b9):
kmemleak_alloc_recursive include/linux/kmemleak.h:44 [inline]
slab_post_alloc_hook mm/slub.c:4550 [inline]
slab_alloc_node mm/slub.c:4873 [inline]
__do_kmalloc_node mm/slub.c:5266 [inline]
__kmalloc_noprof+0x3bd/0x560 mm/slub.c:5279
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:5729
free_to_pcs mm/slub.c:5782 [inline]
slab_free mm/slub.c:6177 [inline]
kfree+0x352/0x390 mm/slub.c:6490
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 0xffff8881023e9000 (size 512):
comm "kworker/0:1", pid 10, jiffies 4294937519
hex dump (first 32 bytes):
e0 52 f6 28 81 88 ff ff 00 b6 ad 81 ff ff ff ff .R.(............
00 12 04 00 81 88 ff ff 3c 00 00 00 00 00 00 00 ........<.......
backtrace (crc d8ec9e0d):
kmemleak_alloc_recursive include/linux/kmemleak.h:44 [inline]
slab_post_alloc_hook mm/slub.c:4550 [inline]
slab_alloc_node mm/slub.c:4873 [inline]
__do_kmalloc_node mm/slub.c:5266 [inline]
__kmalloc_noprof+0x3bd/0x560 mm/slub.c:5279
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:5729
free_to_pcs mm/slub.c:5782 [inline]
slab_free mm/slub.c:6177 [inline]
kfree+0x352/0x390 mm/slub.c:6490
blk_free_flush_queue+0x28/0x40 block/blk-flush.c:514
srcu_invoke_callbacks+0x11a/0x1c0 kernel/rcu/srcutree.c:1941
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 0xffff888104850a00 (size 512):
comm "kworker/0:1", pid 10, jiffies 4294937528
hex dump (first 32 bytes):
00 6c 8f 00 81 88 ff ff 00 10 0a 2b 81 88 ff ff .l.........+....
00 12 04 00 81 88 ff ff 3c 00 00 00 00 00 00 00 ........<.......
backtrace (crc c75772dc):
kmemleak_alloc_recursive include/linux/kmemleak.h:44 [inline]
slab_post_alloc_hook mm/slub.c:4550 [inline]
slab_alloc_node mm/slub.c:4873 [inline]
__do_kmalloc_node mm/slub.c:5266 [inline]
__kmalloc_noprof+0x3bd/0x560 mm/slub.c:5279
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:5729
free_to_pcs mm/slub.c:5782 [inline]
slab_free mm/slub.c:6177 [inline]
kfree+0x352/0x390 mm/slub.c:6490
blk_free_flush_queue+0x28/0x40 block/blk-flush.c:514
srcu_invoke_callbacks+0x11a/0x1c0 kernel/rcu/srcutree.c:1941
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 0xffff888104850800 (size 512):
comm "kworker/0:1", pid 10, jiffies 4294937528
hex dump (first 32 bytes):
18 6a 89 26 81 88 ff ff 00 b6 ad 81 ff ff ff ff .j.&............
00 12 04 00 81 88 ff ff 3c 00 00 00 00 00 00 00 ........<.......
backtrace (crc 1ece07b3):
kmemleak_alloc_recursive include/linux/kmemleak.h:44 [inline]
slab_post_alloc_hook mm/slub.c:4550 [inline]
slab_alloc_node mm/slub.c:4873 [inline]
__do_kmalloc_node mm/slub.c:5266 [inline]
__kmalloc_noprof+0x3bd/0x560 mm/slub.c:5279
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:5729
free_to_pcs mm/slub.c:5782 [inline]
slab_free mm/slub.c:6177 [inline]
kfree+0x352/0x390 mm/slub.c:6490
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

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

Tested on:

commit: b29fb882 Merge tag 'v7.0-rc3-ksmbd-server-fixes' of gi..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=13fb694a580000
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=14023016580000