In the Linux kernel, the following vulnerability has been resolved: gfs2: fix memory leaks in gfs2_fill_super error path Fix two memory leaks in the gfs2_fill_super() error handling path when transitioning a filesystem to read-write mo…

Overview

In the Linux kernel, the following vulnerability has been resolved:

gfs2: fix memory leaks in gfs2_fill_super error path

Fix two memory leaks in the gfs2_fill_super() error handling path when transitioning a filesystem to read-write mode fails.

First leak: kthread objects (thread_struct, task_struct, etc.) When gfs2_freeze_lock_shared() fails after init_threads() succeeds, the created kernel threads (logd and quotad) are never destroyed. This occurs because the fail_per_node label doesn't call gfs2_destroy_threads().

Second leak: quota bitmap buffer (8192 bytes) When gfs2_make_fs_rw() fails after gfs2_quota_init() succeeds but before other operations complete, the allocated quota bitmap is never freed.

The fix moves thread cleanup to the fail_per_node label to handle all error paths uniformly. gfs2_destroy_threads() is safe to call unconditionally as it checks for NULL pointers. Quota cleanup is added in gfs2_make_fs_rw() to properly handle the withdrawal case where quota initialization succeeds but the filesystem is then withdrawn.

Thread leak backtrace (gfs2_freeze_lock_shared failure): unreferenced object 0xffff88801d7bca80 (size 4480): copy_process+0x3a1/0x4670 kernel/fork.c:2422 kernel_clone+0xf3/0x6e0 kernel/fork.c:2779 kthread_create_on_node+0x100/0x150 kernel/kthread.c:478 init_threads+0xab/0x350 fs/gfs2/ops_fstype.c:611 gfs2_fill_super+0xe5c/0x1240 fs/gfs2/ops_fstype.c:1265

Quota leak backtrace (gfs2_make_fs_rw failure): unreferenced object 0xffff88812de7c000 (size 8192): gfs2_quota_init+0xe5/0x820 fs/gfs2/quota.c:1409 gfs2_make_fs_rw+0x7a/0xe0 fs/gfs2/super.c:149 gfs2_fill_super+0xfbb/0x1240 fs/gfs2/ops_fstype.c:1275

Affected

• linux_kernel >= 5.10.173, < 5.11
• linux_kernel >= 5.15.99, < 5.16
• linux_kernel >= 6.1.16, < 6.2
• linux_kernel >= 6.2.3, < 6.19.4

Remediation

Upgrade past the affected range:

• linux_kernel 6.19.4