memory leak in prepare_creds (7)

Status: upstream: reported C repro on 2026/08/04 00:09
Subsystems: lsm
Labels: prio:high
[Documentation on labels]
Reported-by: syzbot+53515d23498d641e21ea@syzkaller.appspotmail.com
First crash: 7d05h, last: 4d02h
▶ ▼ ✨ AI Patch Versions (1)
Version Stage Reported Report Link Job
1 moderation 2026/08/04 11:15 Discussion 00823f4e-0b0b-4294-a519-38c6921e12fa
▶ ▼ ✨ AI Jobs (2)
ID Workflow Result Correct Bug Created Started Finished Revision
00823f4e patching ❓ memory leak in prepare_creds (7) 2026/08/04 09:27 2026/08/04 09:27 2026/08/04 11:15 9451e17e
11cec12a assessment-security DenialOfService: ✅ Exploitable: ❌ FilesystemTrigger: ❌ NetworkTrigger: ❌ PeripheralTrigger: ❌ RemoteTrigger: ❌ Unprivileged: ✅ UserNamespace: ✅ VMGuestTrigger: ❌ VMHostTrigger: ❌ ❓ memory leak in prepare_creds (7) 2026/07/31 01:40 2026/07/31 01:40 2026/07/31 02:17 aaffb173
▶ ▼ Discussions (1)
Title Replies (including bot) Last reply
[syzbot] [lsm?] memory leak in prepare_creds (7) 0 (1) 2026/08/04 00:09
▶ ▼ Similar bugs (6)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream memory leak in prepare_creds (3) lsm 3 syz, C 24 1290d 1568d 0/29 auto-obsoleted due to no activity on 2023/05/24 05:02
upstream memory leak in prepare_creds (2) lsm 3 syz, C 2 1869d 1964d 20/29 fixed on 2021/11/10 00:50
upstream memory leak in prepare_creds (5) lsm 3 syz, C 60 198d 272d 29/29 fixed on 2026/01/21 09:45
upstream memory leak in prepare_creds (4) lsm 3 syz, C 5 943d 1042d 0/29 auto-obsoleted due to no activity on 2024/04/17 09:09
upstream memory leak in prepare_creds (6) lsm 3 syz, C 2 172d 194d 29/29 fixed on 2026/05/06 16:40
upstream memory leak in prepare_creds lsm 3 syz, C 10 1995d 2169d 19/29 fixed on 2021/03/10 01:48

Sample crash report:
2026/07/30 13:50:02 executed programs: 5
BUG: memory leak
unreferenced object 0xffff88810ab2c540 (size 184):
  comm "syz-executor", pid 5809, jiffies 4294943975
  hex dump (first 32 bytes):
    01 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 706c7ae4):
    kmemleak_alloc_recursive include/linux/kmemleak.h:44 [inline]
    slab_post_alloc_hook mm/slub.c:4597 [inline]
    slab_alloc_node mm/slub.c:4917 [inline]
    kmem_cache_alloc_noprof+0x34f/0x440 mm/slub.c:4931
    prepare_creds+0x22/0x570 kernel/cred.c:185
    copy_creds+0x44/0x290 kernel/cred.c:286
    copy_process+0x988/0x2d70 kernel/fork.c:2153
    kernel_clone+0x101/0x710 kernel/fork.c:2748
    __do_sys_clone+0x7f/0xb0 kernel/fork.c:2889
    do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
    do_syscall_64+0xf8/0x610 arch/x86/entry/syscall_64.c:94
    entry_SYSCALL_64_after_hwframe+0x77/0x7f

BUG: memory leak
unreferenced object 0xffff8881021256c0 (size 32):
  comm "syz-executor", pid 5809, jiffies 4294943975
  hex dump (first 32 bytes):
    00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
    f8 52 0a 00 81 88 ff ff 00 00 00 00 00 00 00 00  .R..............
  backtrace (crc 9ae86290):
    kmemleak_alloc_recursive include/linux/kmemleak.h:44 [inline]
    slab_post_alloc_hook mm/slub.c:4597 [inline]
    slab_alloc_node mm/slub.c:4917 [inline]
    __do_kmalloc_node mm/slub.c:5333 [inline]
    __kmalloc_noprof+0x3bf/0x550 mm/slub.c:5359
    _kmalloc_noprof include/linux/slab.h:992 [inline]
    _kzalloc_noprof include/linux/slab.h:1309 [inline]
    lsm_blob_alloc+0x4d/0x80 security/security.c:218
    lsm_cred_alloc security/security.c:235 [inline]
    security_prepare_creds+0x2d/0x290 security/security.c:2866
    prepare_creds+0x317/0x570 kernel/cred.c:215
    copy_creds+0x44/0x290 kernel/cred.c:286
    copy_process+0x988/0x2d70 kernel/fork.c:2153
    kernel_clone+0x101/0x710 kernel/fork.c:2748
    __do_sys_clone+0x7f/0xb0 kernel/fork.c:2889
    do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
    do_syscall_64+0xf8/0x610 arch/x86/entry/syscall_64.c:94
    entry_SYSCALL_64_after_hwframe+0x77/0x7f

BUG: memory leak
unreferenced object 0xffff8881068d2d00 (size 1272):
  comm "kworker/1:2", pid 2174, jiffies 4294943976
  hex dump (first 32 bytes):
    00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
    28 00 0b 40 00 00 00 00 00 00 00 00 00 00 00 00  (..@............
  backtrace (crc ff0fde65):
    kmemleak_alloc_recursive include/linux/kmemleak.h:44 [inline]
    slab_post_alloc_hook mm/slub.c:4597 [inline]
    slab_alloc_node mm/slub.c:4917 [inline]
    kmem_cache_alloc_noprof+0x34f/0x440 mm/slub.c:4931
    sk_prot_alloc+0x3e/0x1b0 net/core/sock.c:2246
    sk_alloc+0x36/0x3d0 net/core/sock.c:2308
    __vsock_create.constprop.0+0x38/0x2f0 net/vmw_vsock/af_vsock.c:919
    virtio_transport_recv_listen net/vmw_vsock/virtio_transport_common.c:1721 [inline]
    virtio_transport_recv_pkt+0x8fa/0x16c0 net/vmw_vsock/virtio_transport_common.c:1847
    vsock_loopback_work+0x104/0x140 net/vmw_vsock/vsock_loopback.c:142
    process_one_work+0x277/0x5a0 kernel/workqueue.c:3322
    process_scheduled_works kernel/workqueue.c:3405 [inline]
    worker_thread+0x255/0x4a0 kernel/workqueue.c:3486
    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 0xffff8881145bbb60 (size 32):
  comm "kworker/1:2", pid 2174, jiffies 4294943976
  hex dump (first 32 bytes):
    f8 52 0a 00 81 88 ff ff 00 00 00 00 00 00 00 00  .R..............
    00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
  backtrace (crc 42a7bc0e):
    kmemleak_alloc_recursive include/linux/kmemleak.h:44 [inline]
    slab_post_alloc_hook mm/slub.c:4597 [inline]
    slab_alloc_node mm/slub.c:4917 [inline]
    __do_kmalloc_node mm/slub.c:5333 [inline]
    __kmalloc_noprof+0x3bf/0x550 mm/slub.c:5359
    _kmalloc_noprof include/linux/slab.h:992 [inline]
    _kzalloc_noprof include/linux/slab.h:1309 [inline]
    lsm_blob_alloc+0x4d/0x80 security/security.c:218
    lsm_sock_alloc security/security.c:4478 [inline]
    security_sk_alloc+0x2d/0x290 security/security.c:4494
    sk_prot_alloc+0x8f/0x1b0 net/core/sock.c:2255
    sk_alloc+0x36/0x3d0 net/core/sock.c:2308
    __vsock_create.constprop.0+0x38/0x2f0 net/vmw_vsock/af_vsock.c:919
    virtio_transport_recv_listen net/vmw_vsock/virtio_transport_common.c:1721 [inline]
    virtio_transport_recv_pkt+0x8fa/0x16c0 net/vmw_vsock/virtio_transport_common.c:1847
    vsock_loopback_work+0x104/0x140 net/vmw_vsock/vsock_loopback.c:142
    process_one_work+0x277/0x5a0 kernel/workqueue.c:3322
    process_scheduled_works kernel/workqueue.c:3405 [inline]
    worker_thread+0x255/0x4a0 kernel/workqueue.c:3486
    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 0xffff88811573e0c0 (size 96):
  comm "kworker/1:2", pid 2174, jiffies 4294943976
  hex dump (first 32 bytes):
    00 2d 8d 06 81 88 ff ff 00 00 00 00 00 00 00 00  .-..............
    00 00 00 00 00 00 00 00 00 00 04 00 00 00 00 00  ................
  backtrace (crc af6af911):
    kmemleak_alloc_recursive include/linux/kmemleak.h:44 [inline]
    slab_post_alloc_hook mm/slub.c:4597 [inline]
    slab_alloc_node mm/slub.c:4917 [inline]
    __kmalloc_cache_noprof+0x356/0x440 mm/slub.c:5485
    _kmalloc_noprof include/linux/slab.h:988 [inline]
    _kzalloc_noprof include/linux/slab.h:1309 [inline]
    virtio_transport_do_socket_init+0x2b/0xf0 net/vmw_vsock/virtio_transport_common.c:1056
    vsock_assign_transport+0x3a3/0x460 net/vmw_vsock/af_vsock.c:670
    virtio_transport_recv_listen net/vmw_vsock/virtio_transport_common.c:1737 [inline]
    virtio_transport_recv_pkt+0x956/0x16c0 net/vmw_vsock/virtio_transport_common.c:1847
    vsock_loopback_work+0x104/0x140 net/vmw_vsock/vsock_loopback.c:142
    process_one_work+0x277/0x5a0 kernel/workqueue.c:3322
    process_scheduled_works kernel/workqueue.c:3405 [inline]
    worker_thread+0x255/0x4a0 kernel/workqueue.c:3486
    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 0xffff8881068d2800 (size 1272):
  comm "kworker/1:2", pid 2174, jiffies 4294943977
  hex dump (first 32 bytes):
    00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
    28 00 0b 40 00 00 00 00 00 00 00 00 00 00 00 00  (..@............
  backtrace (crc e503b7a6):
    kmemleak_alloc_recursive include/linux/kmemleak.h:44 [inline]
    slab_post_alloc_hook mm/slub.c:4597 [inline]
    slab_alloc_node mm/slub.c:4917 [inline]
    kmem_cache_alloc_noprof+0x34f/0x440 mm/slub.c:4931
    sk_prot_alloc+0x3e/0x1b0 net/core/sock.c:2246
    sk_alloc+0x36/0x3d0 net/core/sock.c:2308
    __vsock_create.constprop.0+0x38/0x2f0 net/vmw_vsock/af_vsock.c:919
    virtio_transport_recv_listen net/vmw_vsock/virtio_transport_common.c:1721 [inline]
    virtio_transport_recv_pkt+0x8fa/0x16c0 net/vmw_vsock/virtio_transport_common.c:1847
    vsock_loopback_work+0x104/0x140 net/vmw_vsock/vsock_loopback.c:142
    process_one_work+0x277/0x5a0 kernel/workqueue.c:3322
    process_scheduled_works kernel/workqueue.c:3405 [inline]
    worker_thread+0x255/0x4a0 kernel/workqueue.c:3486
    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

Crashes (2):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/07/30 13:50 upstream 11028ab62899 2377cd3d .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci-upstream-gce-leak memory leak in prepare_creds
2026/08/02 16:14 upstream 2d2338c93da7 e611ffe1 .config console log report syz / log [disk image] [vmlinux] [kernel image] ci-upstream-gce-leak memory leak in prepare_creds
* Struck through repros no longer work on HEAD.