[syzbot] memory leak in dev_exception_add

Tue Jul 13 18:07:24 UTC 2021

Hello,

syzbot found the following issue on:

HEAD commit:    3dbdb38e Merge branch 'for-5.14' of git://git.kernel.org/p..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=1518cffc300000
kernel config:  https://syzkaller.appspot.com/x/.config?x=55ac6a927d7e3fe9
dashboard link: https://syzkaller.appspot.com/bug?extid=988c8a25ad1677559236
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=1500e772300000

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+988c8a25ad1677559236 at syzkaller.appspotmail.com

BUG: memory leak
unreferenced object 0xffff88810d3a4300 (size 64):
  comm "systemd", pid 1, jiffies 4294938536 (age 1351.150s)
  hex dump (first 32 bytes):
    01 00 00 00 03 00 00 00 02 00 07 00 00 00 00 00  ................
    10 04 2b 0d 81 88 ff ff 22 01 00 00 00 00 ad de  ..+.....".......
  backtrace:
    [<ffffffff81479633>] kmemdup+0x23/0x50 mm/util.c:128
    [<ffffffff8217485f>] kmemdup include/linux/fortify-string.h:270 [inline]
    [<ffffffff8217485f>] dev_exception_add+0x2f/0x160 security/device_cgroup.c:94
    [<ffffffff82175812>] devcgroup_update_access security/device_cgroup.c:734 [inline]
    [<ffffffff82175812>] devcgroup_access_write+0x8c2/0x9e0 security/device_cgroup.c:764
    [<ffffffff813198bd>] cgroup_file_write+0x10d/0x260 kernel/cgroup/cgroup.c:3814
    [<ffffffff81690535>] kernfs_fop_write_iter+0x1b5/0x270 fs/kernfs/file.c:296
    [<ffffffff81560eb7>] call_write_iter include/linux/fs.h:2114 [inline]
    [<ffffffff81560eb7>] new_sync_write+0x1d7/0x2b0 fs/read_write.c:518
    [<ffffffff81564531>] vfs_write+0x351/0x400 fs/read_write.c:605
    [<ffffffff8156481d>] ksys_write+0x9d/0x160 fs/read_write.c:658
    [<ffffffff8439b235>] do_syscall_x64 arch/x86/entry/common.c:50 [inline]
    [<ffffffff8439b235>] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
    [<ffffffff84400068>] entry_SYSCALL_64_after_hwframe+0x44/0xae

BUG: memory leak
unreferenced object 0xffff88810d2b0400 (size 64):
  comm "systemd", pid 1, jiffies 4294938537 (age 1351.140s)
  hex dump (first 32 bytes):
    01 00 00 00 05 00 00 00 02 00 07 00 00 00 00 00  ................
    90 ac 3b 0d 81 88 ff ff 22 01 00 00 00 00 ad de  ..;.....".......
  backtrace:
    [<ffffffff81479633>] kmemdup+0x23/0x50 mm/util.c:128
    [<ffffffff8217485f>] kmemdup include/linux/fortify-string.h:270 [inline]
    [<ffffffff8217485f>] dev_exception_add+0x2f/0x160 security/device_cgroup.c:94
    [<ffffffff82175812>] devcgroup_update_access security/device_cgroup.c:734 [inline]
    [<ffffffff82175812>] devcgroup_access_write+0x8c2/0x9e0 security/device_cgroup.c:764
    [<ffffffff813198bd>] cgroup_file_write+0x10d/0x260 kernel/cgroup/cgroup.c:3814
    [<ffffffff81690535>] kernfs_fop_write_iter+0x1b5/0x270 fs/kernfs/file.c:296
    [<ffffffff81560eb7>] call_write_iter include/linux/fs.h:2114 [inline]
    [<ffffffff81560eb7>] new_sync_write+0x1d7/0x2b0 fs/read_write.c:518
    [<ffffffff81564531>] vfs_write+0x351/0x400 fs/read_write.c:605
    [<ffffffff8156481d>] ksys_write+0x9d/0x160 fs/read_write.c:658
    [<ffffffff8439b235>] do_syscall_x64 arch/x86/entry/common.c:50 [inline]
    [<ffffffff8439b235>] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
    [<ffffffff84400068>] entry_SYSCALL_64_after_hwframe+0x44/0xae

BUG: memory leak
unreferenced object 0xffff88810d3bac80 (size 64):
  comm "systemd", pid 1, jiffies 4294938537 (age 1351.140s)
  hex dump (first 32 bytes):
    01 00 00 00 07 00 00 00 02 00 07 00 00 00 00 00  ................
    50 84 31 0d 81 88 ff ff 22 01 00 00 00 00 ad de  P.1.....".......
  backtrace:
    [<ffffffff81479633>] kmemdup+0x23/0x50 mm/util.c:128
    [<ffffffff8217485f>] kmemdup include/linux/fortify-string.h:270 [inline]
    [<ffffffff8217485f>] dev_exception_add+0x2f/0x160 security/device_cgroup.c:94
    [<ffffffff82175812>] devcgroup_update_access security/device_cgroup.c:734 [inline]
    [<ffffffff82175812>] devcgroup_access_write+0x8c2/0x9e0 security/device_cgroup.c:764
    [<ffffffff813198bd>] cgroup_file_write+0x10d/0x260 kernel/cgroup/cgroup.c:3814
    [<ffffffff81690535>] kernfs_fop_write_iter+0x1b5/0x270 fs/kernfs/file.c:296
    [<ffffffff81560eb7>] call_write_iter include/linux/fs.h:2114 [inline]
    [<ffffffff81560eb7>] new_sync_write+0x1d7/0x2b0 fs/read_write.c:518
    [<ffffffff81564531>] vfs_write+0x351/0x400 fs/read_write.c:605
    [<ffffffff8156481d>] ksys_write+0x9d/0x160 fs/read_write.c:658
    [<ffffffff8439b235>] do_syscall_x64 arch/x86/entry/common.c:50 [inline]
    [<ffffffff8439b235>] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
    [<ffffffff84400068>] entry_SYSCALL_64_after_hwframe+0x44/0xae

BUG: memory leak
unreferenced object 0xffff88810d318440 (size 64):
  comm "systemd", pid 1, jiffies 4294938537 (age 1351.140s)
  hex dump (first 32 bytes):
    01 00 00 00 08 00 00 00 02 00 07 00 00 00 00 00  ................
    d0 aa 3b 0d 81 88 ff ff 22 01 00 00 00 00 ad de  ..;.....".......
  backtrace:
    [<ffffffff81479633>] kmemdup+0x23/0x50 mm/util.c:128
    [<ffffffff8217485f>] kmemdup include/linux/fortify-string.h:270 [inline]
    [<ffffffff8217485f>] dev_exception_add+0x2f/0x160 security/device_cgroup.c:94
    [<ffffffff82175812>] devcgroup_update_access security/device_cgroup.c:734 [inline]
    [<ffffffff82175812>] devcgroup_access_write+0x8c2/0x9e0 security/device_cgroup.c:764
    [<ffffffff813198bd>] cgroup_file_write+0x10d/0x260 kernel/cgroup/cgroup.c:3814
    [<ffffffff81690535>] kernfs_fop_write_iter+0x1b5/0x270 fs/kernfs/file.c:296
    [<ffffffff81560eb7>] call_write_iter include/linux/fs.h:2114 [inline]
    [<ffffffff81560eb7>] new_sync_write+0x1d7/0x2b0 fs/read_write.c:518
    [<ffffffff81564531>] vfs_write+0x351/0x400 fs/read_write.c:605
    [<ffffffff8156481d>] ksys_write+0x9d/0x160 fs/read_write.c:658
    [<ffffffff8439b235>] do_syscall_x64 arch/x86/entry/common.c:50 [inline]
    [<ffffffff8439b235>] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
    [<ffffffff84400068>] entry_SYSCALL_64_after_hwframe+0x44/0xae

[ 1363.912106][    C1]

---
This report is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzkaller at googlegroups.com.

syzbot will keep track of this issue. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
syzbot can test patches for this issue, for details see:
https://goo.gl/tpsmEJ#testing-patches