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CVE-2021-47119

ext4: fix memory leak in ext4_fill_super PUBLISHED

Description (CNA)

In the Linux kernel, the following vulnerability has been resolved: ext4: fix memory leak in ext4_fill_super Buffer head references must be released before calling kill_bdev(); otherwise the buffer head (and its page referenced by b_data) will not be freed by kill_bdev, and subsequently that bh will be leaked. If blocksizes differ, sb_set_blocksize() will kill current buffers and page cache by using kill_bdev(). And then super block will be reread again but using correct blocksize this time. sb_set_blocksize() didn't fully free superblock page and buffer head, and being busy, they were not freed and instead leaked. This can easily be reproduced by calling an infinite loop of: systemctl start <ext4_on_lvm>.mount, and systemctl stop <ext4_on_lvm>.mount ... since systemd creates a cgroup for each slice which it mounts, and the bh leak get amplified by a dying memory cgroup that also never gets freed, and memory consumption is much more easily noticed.

Affected (CNA)

Vendor / productVersions
Linux / Linuxaffected ac27a0ec112a089f1a5102bc8dffc79c8c815571 before 01d349a481f0591230300a9171330136f9159bcd; affected ac27a0ec112a089f1a5102bc8dffc79c8c815571 before 1385b23396d511d5233b8b921ac3058b3f86a5e1; affected ac27a0ec112a089f1a5102bc8dffc79c8c815571 before afd09b617db3786b6ef3dc43e28fe728cfea84df
Linux / Linuxaffected 2.6.19; unaffected 0 before 2.6.19; unaffected 5.10.43 through 5.10.*; unaffected 5.12.10 through 5.12.*; unaffected 5.13 through *

CWE

No CWE identifiers supplied.

References

ADP enrichment

CISA-ADP

No English description supplied.

No references supplied.

CVE

No English description supplied.