syzbot


memory leak in __kfree_rcu_sheaf

Status: upstream: reported syz repro on 2026/02/09 18:26
Subsystems: mm f2fs exfat
[Documentation on labels]
Reported-by: syzbot+cae7809e9dc1459e4e63@syzkaller.appspotmail.com
First crash: 4d12h, last: 4d12h
Discussions (1)
Title Replies (including bot) Last reply
[syzbot] [mm?] [f2fs?] [exfat?] memory leak in __kfree_rcu_sheaf 0 (1) 2026/02/09 18:26

Sample crash report:
BUG: memory leak
unreferenced object 0xffff888113218600 (size 512):
  comm "sed", pid 6046, jiffies 4294945902
  hex dump (first 32 bytes):
    00 8e 13 29 81 88 ff ff 00 12 86 27 81 88 ff ff  ...).......'....
    00 5a 04 00 81 88 ff ff 00 00 00 00 00 00 00 00  .Z..............
  backtrace (crc 49909e19):
    kmemleak_alloc_recursive include/linux/kmemleak.h:44 [inline]
    slab_post_alloc_hook mm/slub.c:4958 [inline]
    slab_alloc_node mm/slub.c:5263 [inline]
    __do_kmalloc_node mm/slub.c:5656 [inline]
    __kmalloc_noprof+0x465/0x680 mm/slub.c:5669
    kmalloc_noprof include/linux/slab.h:961 [inline]
    kzalloc_noprof include/linux/slab.h:1094 [inline]
    alloc_empty_sheaf+0x36/0x50 mm/slub.c:2618
    __kfree_rcu_sheaf+0x155/0x210 mm/slub.c:6304
    kfree_rcu_sheaf mm/slab_common.c:1631 [inline]
    kvfree_call_rcu+0x202/0x3d0 mm/slab_common.c:1981
    ma_free_rcu lib/maple_tree.c:208 [inline]
    ma_free_rcu+0x29/0x40 lib/maple_tree.c:205
    mas_free lib/maple_tree.c:1174 [inline]
    mas_replace_node lib/maple_tree.c:1581 [inline]
    mas_wr_node_store+0x5fc/0x730 lib/maple_tree.c:3553
    mas_wr_store_entry+0x4eb/0x760 lib/maple_tree.c:3764
    mas_store_prealloc+0x358/0x740 lib/maple_tree.c:5169
    vma_iter_store_overwrite mm/vma.h:544 [inline]
    commit_merge+0x28e/0x490 mm/vma.c:763
    vma_expand+0x264/0x460 mm/vma.c:1200
    vma_merge_new_range+0xe3/0x350 mm/vma.c:1099
    __mmap_region+0x54b/0x15b0 mm/vma.c:2747
    mmap_region+0xfb/0x1e0 mm/vma.c:2830
    do_mmap+0x7ac/0xb80 mm/mmap.c:558
    vm_mmap_pgoff+0x1a6/0x2d0 mm/util.c:581
    ksys_mmap_pgoff+0x233/0x2d0 mm/mmap.c:604

BUG: memory leak
unreferenced object 0xffff888127861200 (size 512):
  comm "udevd", pid 6236, jiffies 4294948784
  hex dump (first 32 bytes):
    00 86 21 13 81 88 ff ff 18 e0 05 00 81 88 ff ff  ..!.............
    00 5a 04 00 81 88 ff ff 00 00 00 00 00 00 00 00  .Z..............
  backtrace (crc 5b72581e):
    kmemleak_alloc_recursive include/linux/kmemleak.h:44 [inline]
    slab_post_alloc_hook mm/slub.c:4958 [inline]
    slab_alloc_node mm/slub.c:5263 [inline]
    __do_kmalloc_node mm/slub.c:5656 [inline]
    __kmalloc_noprof+0x465/0x680 mm/slub.c:5669
    kmalloc_noprof include/linux/slab.h:961 [inline]
    kzalloc_noprof include/linux/slab.h:1094 [inline]
    alloc_empty_sheaf+0x36/0x50 mm/slub.c:2618
    __kfree_rcu_sheaf+0x155/0x210 mm/slub.c:6304
    kfree_rcu_sheaf mm/slab_common.c:1631 [inline]
    kvfree_call_rcu+0x202/0x3d0 mm/slab_common.c:1981
    ma_free_rcu lib/maple_tree.c:208 [inline]
    ma_free_rcu+0x29/0x40 lib/maple_tree.c:205
    mas_topiary_node lib/maple_tree.c:2311 [inline]
    mas_topiary_node lib/maple_tree.c:2299 [inline]
    mas_topiary_replace+0xb0f/0x1400 lib/maple_tree.c:2410
    mas_wmb_replace lib/maple_tree.c:2433 [inline]
    mas_spanning_rebalance+0x14e1/0x24b0 lib/maple_tree.c:2738
    mas_wr_spanning_store+0x983/0x10d0 lib/maple_tree.c:3479
    mas_wr_store_entry+0x4d5/0x760 lib/maple_tree.c:3767
    mas_store_gfp+0x341/0x640 lib/maple_tree.c:5138
    vma_iter_clear_gfp include/linux/mm.h:1141 [inline]
    do_vmi_align_munmap+0x259/0x2d0 mm/vma.c:1574
    do_vmi_munmap+0x17c/0x280 mm/vma.c:1627
    __vm_munmap+0xec/0x200 mm/vma.c:3247
    __do_sys_munmap mm/mmap.c:1077 [inline]
    __se_sys_munmap mm/mmap.c:1074 [inline]
    __x64_sys_munmap+0x1f/0x30 mm/mmap.c:1074
    do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
    do_syscall_64+0xa4/0xf80 arch/x86/entry/syscall_64.c:94
    entry_SYSCALL_64_after_hwframe+0x77/0x7f

BUG: memory leak
unreferenced object 0xffff88812c458000 (size 4480):
  comm "udevd", pid 5181, jiffies 4294950983
  hex dump (first 32 bytes):
    01 00 08 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
    00 00 00 00 00 00 00 00 80 00 00 00 00 00 00 00  ................
  backtrace (crc ad4af9e6):
    kmemleak_alloc_recursive include/linux/kmemleak.h:44 [inline]
    slab_post_alloc_hook mm/slub.c:4958 [inline]
    slab_alloc_node mm/slub.c:5263 [inline]
    kmem_cache_alloc_node_noprof+0x422/0x590 mm/slub.c:5315
    alloc_task_struct_node kernel/fork.c:184 [inline]
    dup_task_struct kernel/fork.c:915 [inline]
    copy_process+0x286/0x2870 kernel/fork.c:2052
    kernel_clone+0xac/0x6e0 kernel/fork.c:2651
    __do_sys_clone+0x7f/0xb0 kernel/fork.c:2792
    do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
    do_syscall_64+0xa4/0xf80 arch/x86/entry/syscall_64.c:94
    entry_SYSCALL_64_after_hwframe+0x77/0x7f

BUG: memory leak
unreferenced object 0xffff8881274a1540 (size 184):
  comm "udevd", pid 5181, jiffies 4294950983
  hex dump (first 32 bytes):
    02 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
    00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
  backtrace (crc 54e589bc):
    kmemleak_alloc_recursive include/linux/kmemleak.h:44 [inline]
    slab_post_alloc_hook mm/slub.c:4958 [inline]
    slab_alloc_node mm/slub.c:5263 [inline]
    kmem_cache_alloc_noprof+0x412/0x580 mm/slub.c:5270
    prepare_creds+0x22/0x600 kernel/cred.c:185
    copy_creds+0x44/0x290 kernel/cred.c:286
    copy_process+0x7a7/0x2870 kernel/fork.c:2086
    kernel_clone+0xac/0x6e0 kernel/fork.c:2651
    __do_sys_clone+0x7f/0xb0 kernel/fork.c:2792
    do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
    do_syscall_64+0xa4/0xf80 arch/x86/entry/syscall_64.c:94
    entry_SYSCALL_64_after_hwframe+0x77/0x7f

BUG: memory leak
unreferenced object 0xffff888109639020 (size 32):
  comm "udevd", pid 5181, jiffies 4294950983
  hex dump (first 32 bytes):
    00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
    f8 52 86 00 81 88 ff ff 00 00 00 00 00 00 00 00  .R..............
  backtrace (crc 336e1c5f):
    kmemleak_alloc_recursive include/linux/kmemleak.h:44 [inline]
    slab_post_alloc_hook mm/slub.c:4958 [inline]
    slab_alloc_node mm/slub.c:5263 [inline]
    __do_kmalloc_node mm/slub.c:5656 [inline]
    __kmalloc_noprof+0x465/0x680 mm/slub.c:5669
    kmalloc_noprof include/linux/slab.h:961 [inline]
    kzalloc_noprof include/linux/slab.h:1094 [inline]
    lsm_blob_alloc+0x4d/0x80 security/security.c:192
    lsm_cred_alloc security/security.c:209 [inline]
    security_prepare_creds+0x2d/0x290 security/security.c:2763
    prepare_creds+0x395/0x600 kernel/cred.c:215
    copy_creds+0x44/0x290 kernel/cred.c:286
    copy_process+0x7a7/0x2870 kernel/fork.c:2086
    kernel_clone+0xac/0x6e0 kernel/fork.c:2651
    __do_sys_clone+0x7f/0xb0 kernel/fork.c:2792
    do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
    do_syscall_64+0xa4/0xf80 arch/x86/entry/syscall_64.c:94
    entry_SYSCALL_64_after_hwframe+0x77/0x7f

BUG: memory leak
unreferenced object 0xffff888126fdbd80 (size 64):
  comm "udevd", pid 5181, jiffies 4294950983
  hex dump (first 32 bytes):
    c0 c3 4e 46 81 88 ff ff 00 00 00 00 00 00 00 00  ..NF............
    00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
  backtrace (crc 508a43e4):
    kmemleak_alloc_recursive include/linux/kmemleak.h:44 [inline]
    slab_post_alloc_hook mm/slub.c:4958 [inline]
    slab_alloc_node mm/slub.c:5263 [inline]
    __do_kmalloc_node mm/slub.c:5656 [inline]
    __kmalloc_noprof+0x465/0x680 mm/slub.c:5669
    kmalloc_noprof include/linux/slab.h:961 [inline]
    kzalloc_noprof include/linux/slab.h:1094 [inline]
    lsm_blob_alloc+0x4d/0x80 security/security.c:192
    lsm_task_alloc security/security.c:244 [inline]
    security_task_alloc+0x2a/0x260 security/security.c:2682
    copy_process+0xf07/0x2870 kernel/fork.c:2203
    kernel_clone+0xac/0x6e0 kernel/fork.c:2651
    __do_sys_clone+0x7f/0xb0 kernel/fork.c:2792
    do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
    do_syscall_64+0xa4/0xf80 arch/x86/entry/syscall_64.c:94
    entry_SYSCALL_64_after_hwframe+0x77/0x7f

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

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/02/08 12:45 upstream e7aa57247700 4c131dc4 .config console log report syz / log [disk image] [vmlinux] [kernel image] [mounted in repro (corrupt fs)] ci-upstream-gce-leak memory leak in __kfree_rcu_sheaf
* Struck through repros no longer work on HEAD.