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

syzbot
2026-05-04T21:12:03Z

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):
40 a0 ce 2f 81 88 ff ff e0 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 6fa78c59):
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:5414
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 0xffff888100902c00 (size 512):
comm "kthreadd", pid 2, jiffies 4294937340
hex dump (first 32 bytes):
70 09 2a 29 81 88 ff ff e0 13 ad 81 ff ff ff ff p.*)............
00 12 04 00 81 88 ff ff 3c 00 00 00 00 00 00 00 ........<.......
backtrace (crc 638a9d9a):
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_node_noprof+0x3e9/0x4d0 mm/slub.c:5427
kmalloc_node_noprof include/linux/slab.h:1077 [inline]
__get_vm_area_node+0xc6/0x1d0 mm/vmalloc.c:3215
__vmalloc_node_range_noprof+0x1bc/0xdf0 mm/vmalloc.c:4024
__vmalloc_node_noprof+0x71/0x90 mm/vmalloc.c:4124
alloc_thread_stack_node kernel/fork.c:357 [inline]
dup_task_struct kernel/fork.c:926 [inline]
copy_process+0x51f/0x2c90 kernel/fork.c:2090
kernel_clone+0xde/0x700 kernel/fork.c:2721
kernel_thread+0x80/0xb0 kernel/fork.c:2782
create_kthread kernel/kthread.c:459 [inline]
kthreadd+0x186/0x250 kernel/kthread.c:817
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 0xffff888100f8fa00 (size 512):
comm "kworker/1:1", pid 41, jiffies 4294937424
hex dump (first 32 bytes):
38 42 0d 30 81 88 ff ff e0 13 ad 81 ff ff ff ff 8B.0............
00 12 04 00 81 88 ff ff 3c 00 00 00 00 00 00 00 ........<.......
backtrace (crc 185e046f):
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:5761
free_to_pcs mm/slub.c:5814 [inline]
slab_free mm/slub.c:6253 [inline]
kfree+0x361/0x3a0 mm/slub.c:6565
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 0xffff88810255bc00 (size 512):
comm "kworker/u8:2", pid 498, jiffies 4294937434
hex dump (first 32 bytes):
80 35 67 2e 81 88 ff ff e0 13 ad 81 ff ff ff ff .5g.............
00 12 04 00 81 88 ff ff 3c 00 00 00 00 00 00 00 ........<.......
backtrace (crc 804b7261):
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:5761
free_to_pcs mm/slub.c:5814 [inline]
slab_free mm/slub.c:6253 [inline]
kfree+0x361/0x3a0 mm/slub.c:6565
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 0xffff88810256da00 (size 512):
comm "kworker/0:1", pid 10, jiffies 4294937506
hex dump (first 32 bytes):
40 40 38 2d 81 88 ff ff e0 13 ad 81 ff ff ff ff @@8-............
00 12 04 00 81 88 ff ff 3c 00 00 00 00 00 00 00 ........<.......
backtrace (crc e83216dd):
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:5761
free_to_pcs mm/slub.c:5814 [inline]
slab_free mm/slub.c:6253 [inline]
kfree+0x361/0x3a0 mm/slub.c:6565
blk_free_flush_queue+0x28/0x40 block/blk-flush.c:514
srcu_invoke_callbacks+0x11a/0x1c0 kernel/rcu/srcutree.c:1917
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 0xffff8881069d1400 (size 512):
comm "kworker/0:1", pid 10, jiffies 4294937917
hex dump (first 32 bytes):
78 b7 d0 2f 81 88 ff ff e0 13 ad 81 ff ff ff ff x../............
00 12 04 00 81 88 ff ff 3c 00 00 00 00 00 00 00 ........<.......
backtrace (crc 927c2de1):
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:5761
free_to_pcs mm/slub.c:5814 [inline]
slab_free mm/slub.c:6253 [inline]
kfree+0x361/0x3a0 mm/slub.c:6565
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

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

Tested on:

commit: c7e4e4d5 Merge tag 'for-linus-7.1-2' of https://github..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=16963a36580000
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=1650eb26580000