Description

In the Linux kernel, the following vulnerability has been resolved: nilfs2: fix potential bug in end_buffer_async_write According to a syzbot report, end_buffer_async_write(), which handles the completion of block device writes, may detect abnormal condition of the buffer async_write flag and cause a BUG_ON failure when using nilfs2. Nilfs2 itself does not use end_buffer_async_write(). But, the async_write flag is now used as a marker by commit 7f42ec394156 ("nilfs2: fix issue with race condition of competition between segments for dirty blocks") as a means of resolving double list insertion of dirty blocks in nilfs_lookup_dirty_data_buffers() and nilfs_lookup_node_buffers() and the resulting crash. This modification is safe as long as it is used for file data and b-tree node blocks where the page caches are independent. However, it was irrelevant and redundant to also introduce async_write for segment summary and super root blocks that share buffers with the backing device. This led to the possibility that the BUG_ON check in end_buffer_async_write would fail as described above, if independent writebacks of the backing device occurred in parallel. The use of async_write for segment summary buffers has already been removed in a previous change. Fix this issue by removing the manipulation of the async_write flag for the remaining super root block buffer.

Severity

 

CVSS Version 3.x CVSS Version 2.0

CVSS 3.x Severity and Metrics:

NIST: NVD

Base Score:  N/A

NVD assessment not yet provided.

NVD Analysts use publicly available information to associate vector strings and CVSS scores. We also display any CVSS information provided within the CVE List from the CNA.

Note: NVD Analysts have not published a CVSS score for this CVE at this time. NVD Analysts use publicly available information at the time of analysis to associate CVSS vector strings.

CVSS 2.0 Severity and Metrics:

NIST: NVD

Base Score: N/A

NVD assessment not yet provided.

NVD Analysts use publicly available information to associate vector strings and CVSS scores. We also display any CVSS information provided within the CVE List from the CNA.

Note: NVD Analysts have not published a CVSS score for this CVE at this time. NVD Analysts use publicly available information at the time of analysis to associate CVSS vector strings.

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

nilfs2: fix potential bug in end_buffer_async_write

According to a syzbot report, end_buffer_async_write(), which handles the
completion of block device writes, may detect abnormal condition of the
buffer async_write flag and cause a BUG_ON failure when using nilfs2.

Nilfs2 itself does not use end_buffer_async_write().  But, the async_write
flag is now used as a marker by commit 7f42ec394156 ("nilfs2: fix issue
with race cond

kernel.org https://git.kernel.org/stable/c/2c3bdba00283a6c7a5b19481a59a730f46063803 [No types assigned]

kernel.org https://git.kernel.org/stable/c/5bc09b397cbf1221f8a8aacb1152650c9195b02b [No types assigned]

kernel.org https://git.kernel.org/stable/c/626daab3811b772086aef1bf8eed3ffe6f523eff [No types assigned]

kernel.org https://git.kernel.org/stable/c/6589f0f72f8edd1fa11adce4eedbd3615f2e78ab [No types assigned]

kernel.org https://git.kernel.org/stable/c/8fa90634ec3e9cc50f42dd605eec60f2d146ced8 [No types assigned]

kernel.org https://git.kernel.org/stable/c/c4a09fdac625e64abe478dcf88bfa20406616928 [No types assigned]

kernel.org https://git.kernel.org/stable/c/d31c8721e816eff5ca6573cc487754f357c093cd [No types assigned]

kernel.org https://git.kernel.org/stable/c/f3e4963566f58726d3265a727116a42b591f6596 [No types assigned]