syzbot


memory leak in prepare_kernel_cred

Status: upstream: reported C repro on 2021/09/20 15:42
Reported-by: syzbot+b214edc6e43f8da65554@syzkaller.appspotmail.com
First crash: 374d, last: 374d
Patch testing requests:
Created Duration User Patch Repo Result
2022/03/23 13:30 15m nogikh@google.com upstream OK
2022/03/23 13:26 15m k.kahurani@gmail.com upstream OK
2021/10/01 06:07 16m phind.uet@gmail.com linux-next OK

Sample crash report:
write to /proc/sys/kernel/hung_task_check_interval_secs failed: No such file or directory
write to /proc/sys/kernel/softlockup_all_cpu_backtrace failed: No such file or directory
BUG: memory leak
unreferenced object 0xffff8881046d5480 (size 176):
  comm "kworker/u4:0", pid 6631, jiffies 4294994696 (age 35.750s)
  hex dump (first 32 bytes):
    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 00  ................
  backtrace:
    [<ffffffff81275931>] prepare_kernel_cred+0x21/0x2e0 kernel/cred.c:724
    [<ffffffff8125fc6d>] call_usermodehelper_exec_async+0x5d/0x1c0 kernel/umh.c:91
    [<ffffffff8100234f>] ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295

BUG: memory leak
unreferenced object 0xffff888102054040 (size 32):
  comm "kworker/u4:0", pid 6631, jiffies 4294994696 (age 35.750s)
  hex dump (first 32 bytes):
    00 00 00 00 00 00 00 00 b0 12 05 40 81 88 ff ff  ...........@....
    00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
  backtrace:
    [<ffffffff8213e79f>] lsm_cred_alloc security/security.c:537 [inline]
    [<ffffffff8213e79f>] security_prepare_creds+0x9f/0xc0 security/security.c:1691
    [<ffffffff81275ab5>] prepare_kernel_cred+0x1a5/0x2e0 kernel/cred.c:760
    [<ffffffff8125fc6d>] call_usermodehelper_exec_async+0x5d/0x1c0 kernel/umh.c:91
    [<ffffffff8100234f>] ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295

BUG: memory leak
unreferenced object 0xffff8881046d50c0 (size 176):
  comm "kworker/u4:0", pid 6633, jiffies 4294994696 (age 35.750s)
  hex dump (first 32 bytes):
    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 00  ................
  backtrace:
    [<ffffffff81275931>] prepare_kernel_cred+0x21/0x2e0 kernel/cred.c:724
    [<ffffffff8125fc6d>] call_usermodehelper_exec_async+0x5d/0x1c0 kernel/umh.c:91
    [<ffffffff8100234f>] ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295

BUG: memory leak
unreferenced object 0xffff88810493f6c0 (size 176):
  comm "kworker/u4:0", pid 6634, jiffies 4294994696 (age 35.750s)
  hex dump (first 32 bytes):
    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 00  ................
  backtrace:
    [<ffffffff81275931>] prepare_kernel_cred+0x21/0x2e0 kernel/cred.c:724
    [<ffffffff8125fc6d>] call_usermodehelper_exec_async+0x5d/0x1c0 kernel/umh.c:91
    [<ffffffff8100234f>] ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295

BUG: memory leak
unreferenced object 0xffff888104cec5e0 (size 32):
  comm "kworker/u4:0", pid 6634, jiffies 4294994696 (age 35.750s)
  hex dump (first 32 bytes):
    00 00 00 00 00 00 00 00 b0 12 05 40 81 88 ff ff  ...........@....
    00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
  backtrace:
    [<ffffffff8213e79f>] lsm_cred_alloc security/security.c:537 [inline]
    [<ffffffff8213e79f>] security_prepare_creds+0x9f/0xc0 security/security.c:1691
    [<ffffffff81275ab5>] prepare_kernel_cred+0x1a5/0x2e0 kernel/cred.c:760
    [<ffffffff8125fc6d>] call_usermodehelper_exec_async+0x5d/0x1c0 kernel/umh.c:91
    [<ffffffff8100234f>] ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295

BUG: memory leak
unreferenced object 0xffff88810382b780 (size 176):
  comm "kworker/u4:0", pid 6637, jiffies 4294994700 (age 35.710s)
  hex dump (first 32 bytes):
    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 00  ................
  backtrace:
    [<ffffffff81275931>] prepare_kernel_cred+0x21/0x2e0 kernel/cred.c:724
    [<ffffffff8125fc6d>] call_usermodehelper_exec_async+0x5d/0x1c0 kernel/umh.c:91
    [<ffffffff8100234f>] ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295

BUG: memory leak
unreferenced object 0xffff888102054060 (size 32):
  comm "kworker/u4:0", pid 6637, jiffies 4294994700 (age 35.710s)
  hex dump (first 32 bytes):
    00 00 00 00 00 00 00 00 b0 12 05 40 81 88 ff ff  ...........@....
    00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
  backtrace:
    [<ffffffff8213e79f>] lsm_cred_alloc security/security.c:537 [inline]
    [<ffffffff8213e79f>] security_prepare_creds+0x9f/0xc0 security/security.c:1691
    [<ffffffff81275ab5>] prepare_kernel_cred+0x1a5/0x2e0 kernel/cred.c:760
    [<ffffffff8125fc6d>] call_usermodehelper_exec_async+0x5d/0x1c0 kernel/umh.c:91
    [<ffffffff8100234f>] ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295

BUG: memory leak
unreferenced object 0xffff888104c0a780 (size 176):
  comm "kworker/u4:0", pid 6630, jiffies 4294994702 (age 35.690s)
  hex dump (first 32 bytes):
    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 00  ................
  backtrace:
    [<ffffffff81275931>] prepare_kernel_cred+0x21/0x2e0 kernel/cred.c:724
    [<ffffffff8125fc6d>] call_usermodehelper_exec_async+0x5d/0x1c0 kernel/umh.c:91
    [<ffffffff8100234f>] ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295


Crashes (1):
Manager Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Title
ci-upstream-gce-leak 2021/09/18 19:29 upstream 4357f03d6611 70b76c1d .config log report syz C memory leak in prepare_kernel_cred
* Struck through repros no longer work on HEAD.