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

syzbot
2026-05-03T07:17:02Z

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 0xffff88810005f600 (size 512):
comm "swapper/0", pid 0, jiffies 4294937296
hex dump (first 32 bytes):
e0 e2 ee 2c 81 88 ff ff a0 13 ad 81 ff ff ff ff ...,............
00 12 04 00 81 88 ff ff 3c 00 00 00 00 00 00 00 ........<.......
backtrace (crc 2486057c):
kmemleak_alloc_recursive include/linux/kmemleak.h:44 [inline]
slab_post_alloc_hook mm/slub.c:4574 [inline]
slab_alloc_node mm/slub.c:4898 [inline]
__do_kmalloc_node mm/slub.c:5294 [inline]
__kmalloc_noprof+0x3b7/0x550 mm/slub.c:5307
kmalloc_noprof include/linux/slab.h:954 [inline]
kzalloc_noprof include/linux/slab.h:1188 [inline]
__alloc_empty_sheaf+0x35/0x50 mm/slub.c:2768
alloc_empty_sheaf mm/slub.c:2783 [inline]
__pcs_replace_empty_main+0x22a/0x2a0 mm/slub.c:4646
alloc_from_pcs mm/slub.c:4749 [inline]
slab_alloc_node mm/slub.c:4883 [inline]
__kmalloc_cache_noprof+0x3a6/0x480 mm/slub.c:5410
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:1123
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 0xffff888101d04e00 (size 512):
comm "kworker/u8:5", pid 311, jiffies 4294937428
hex dump (first 32 bytes):
b8 1c b8 28 81 88 ff ff a0 13 ad 81 ff ff ff ff ...(............
00 12 04 00 81 88 ff ff 3c 00 00 00 00 00 00 00 ........<.......
backtrace (crc 1d48d83d):
kmemleak_alloc_recursive include/linux/kmemleak.h:44 [inline]
slab_post_alloc_hook mm/slub.c:4574 [inline]
slab_alloc_node mm/slub.c:4898 [inline]
__do_kmalloc_node mm/slub.c:5294 [inline]
__kmalloc_noprof+0x3b7/0x550 mm/slub.c:5307
kmalloc_noprof include/linux/slab.h:954 [inline]
kzalloc_noprof include/linux/slab.h:1188 [inline]
__alloc_empty_sheaf+0x35/0x50 mm/slub.c:2768
alloc_empty_sheaf mm/slub.c:2783 [inline]
__pcs_replace_full_main+0xdf/0x300 mm/slub.c:5757
free_to_pcs mm/slub.c:5810 [inline]
slab_free mm/slub.c:6249 [inline]
kfree+0x361/0x3a0 mm/slub.c:6561
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+0x219/0x490 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

BUG: memory leak
unreferenced object 0xffff888101d18800 (size 512):
comm "kworker/0:1", pid 10, jiffies 4294937813
hex dump (first 32 bytes):
00 c8 ec 0b 81 88 ff ff 00 18 d3 0b 81 88 ff ff ................
00 12 04 00 81 88 ff ff 00 00 00 00 00 00 00 00 ................
backtrace (crc 307f46be):
kmemleak_alloc_recursive include/linux/kmemleak.h:44 [inline]
slab_post_alloc_hook mm/slub.c:4574 [inline]
slab_alloc_node mm/slub.c:4898 [inline]
__do_kmalloc_node mm/slub.c:5294 [inline]
__kmalloc_noprof+0x3b7/0x550 mm/slub.c:5307
kmalloc_noprof include/linux/slab.h:954 [inline]
kzalloc_noprof include/linux/slab.h:1188 [inline]
__alloc_empty_sheaf+0x35/0x50 mm/slub.c:2768
alloc_empty_sheaf mm/slub.c:2783 [inline]
__pcs_replace_full_main+0xdf/0x300 mm/slub.c:5757
free_to_pcs mm/slub.c:5810 [inline]
slab_free mm/slub.c:6249 [inline]
kfree+0x361/0x3a0 mm/slub.c:6561
vfree mm/vmalloc.c:3476 [inline]
vfree+0x14d/0x3d0 mm/vmalloc.c:3436
delayed_vfree_work+0x29/0x40 mm/vmalloc.c:3392
process_one_work+0x277/0x5b0 kernel/workqueue.c:3302
process_scheduled_works kernel/workqueue.c:3385 [inline]
worker_thread+0x255/0x4a0 kernel/workqueue.c:3466
kthread+0x14e/0x1a0 kernel/kthread.c:436
ret_from_fork+0x219/0x490 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

BUG: memory leak
unreferenced object 0xffff888101d2be00 (size 512):
comm "kworker/0:1", pid 10, jiffies 4294937856
hex dump (first 32 bytes):
c8 2c 04 00 81 88 ff ff 00 90 b7 2a 81 88 ff ff .,.........*....
00 12 04 00 81 88 ff ff 3c 00 00 00 00 00 00 00 ........<.......
backtrace (crc 9ff75ca2):
kmemleak_alloc_recursive include/linux/kmemleak.h:44 [inline]
slab_post_alloc_hook mm/slub.c:4574 [inline]
slab_alloc_node mm/slub.c:4898 [inline]
__do_kmalloc_node mm/slub.c:5294 [inline]
__kmalloc_noprof+0x3b7/0x550 mm/slub.c:5307
kmalloc_noprof include/linux/slab.h:954 [inline]
kzalloc_noprof include/linux/slab.h:1188 [inline]
__alloc_empty_sheaf+0x35/0x50 mm/slub.c:2768
alloc_empty_sheaf mm/slub.c:2783 [inline]
__pcs_replace_full_main+0xdf/0x300 mm/slub.c:5757
free_to_pcs mm/slub.c:5810 [inline]
slab_free mm/slub.c:6249 [inline]
kfree+0x361/0x3a0 mm/slub.c:6561
vfree mm/vmalloc.c:3476 [inline]
vfree+0x14d/0x3d0 mm/vmalloc.c:3436
delayed_vfree_work+0x29/0x40 mm/vmalloc.c:3392
process_one_work+0x277/0x5b0 kernel/workqueue.c:3302
process_scheduled_works kernel/workqueue.c:3385 [inline]
worker_thread+0x255/0x4a0 kernel/workqueue.c:3466
kthread+0x14e/0x1a0 kernel/kthread.c:436
ret_from_fork+0x219/0x490 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

BUG: memory leak
unreferenced object 0xffff888101d2b000 (size 512):
comm "kworker/u8:9", pid 4643, jiffies 4294937873
hex dump (first 32 bytes):
00 72 5a 03 81 88 ff ff c8 2c 04 00 81 88 ff ff .rZ......,......
00 12 04 00 81 88 ff ff 3c 00 00 00 00 00 00 00 ........<.......
backtrace (crc bcccad5b):
kmemleak_alloc_recursive include/linux/kmemleak.h:44 [inline]
slab_post_alloc_hook mm/slub.c:4574 [inline]
slab_alloc_node mm/slub.c:4898 [inline]
__do_kmalloc_node mm/slub.c:5294 [inline]
__kmalloc_noprof+0x3b7/0x550 mm/slub.c:5307
kmalloc_noprof include/linux/slab.h:954 [inline]
kzalloc_noprof include/linux/slab.h:1188 [inline]
__alloc_empty_sheaf+0x35/0x50 mm/slub.c:2768
alloc_empty_sheaf mm/slub.c:2783 [inline]
__pcs_replace_full_main+0xdf/0x300 mm/slub.c:5757
free_to_pcs mm/slub.c:5810 [inline]
slab_free mm/slub.c:6249 [inline]
kfree+0x361/0x3a0 mm/slub.c:6561
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+0x219/0x490 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

BUG: memory leak
unreferenced object 0xffff8881035a7400 (size 512):
comm "udevadm", pid 4981, jiffies 4294938333
hex dump (first 32 bytes):
00 88 b7 2a 81 88 ff ff 00 4e d0 01 81 88 ff ff ...*.....N......
00 12 04 00 81 88 ff ff 00 00 00 00 00 00 00 00 ................
backtrace (crc 82d289ee):
kmemleak_alloc_recursive include/linux/kmemleak.h:44 [inline]
slab_post_alloc_hook mm/slub.c:4574 [inline]
slab_alloc_node mm/slub.c:4898 [inline]
__do_kmalloc_node mm/slub.c:5294 [inline]
__kmalloc_noprof+0x3b7/0x550 mm/slub.c:5307
kmalloc_noprof include/linux/slab.h:954 [inline]
kzalloc_noprof include/linux/slab.h:1188 [inline]
__alloc_empty_sheaf+0x35/0x50 mm/slub.c:2768
alloc_empty_sheaf mm/slub.c:2783 [inline]
__pcs_replace_empty_main+0x22a/0x2a0 mm/slub.c:4646
alloc_from_pcs mm/slub.c:4749 [inline]
slab_alloc_node mm/slub.c:4883 [inline]
__kmalloc_cache_noprof+0x3a6/0x480 mm/slub.c:5410
kmalloc_noprof include/linux/slab.h:950 [inline]
kzalloc_noprof include/linux/slab.h:1188 [inline]
kernfs_get_open_node fs/kernfs/file.c:543 [inline]
kernfs_fop_open+0x4f4/0x580 fs/kernfs/file.c:718
do_dentry_open+0x1fc/0x8c0 fs/open.c:947
vfs_open+0x3d/0x1b0 fs/open.c:1079
do_open fs/namei.c:4699 [inline]
path_openat+0x154d/0x1e20 fs/namei.c:4858
do_file_open+0x121/0x200 fs/namei.c:4887
do_sys_openat2+0xa5/0x140 fs/open.c:1364
do_sys_open fs/open.c:1370 [inline]
__do_sys_openat fs/open.c:1386 [inline]
__se_sys_openat fs/open.c:1381 [inline]
__x64_sys_openat+0x82/0xf0 fs/open.c:1381
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xee/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f

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

Tested on:

commit: 66edb901 Merge tag 'v7.1-p3' of git://git.kernel.org/p..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=13db0ad2580000
kernel config: https://syzkaller.appspot.com/x/.config?x=9645c21cfd1d3e8f
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=153b7ece580000