CVE-2021-47007

f2fs: fix panic during f2fs_resize_fs()

Description

In the Linux kernel, the following vulnerability has been resolved: f2fs: fix panic during f2fs_resize_fs() f2fs_resize_fs() hangs in below callstack with testcase: - mkfs 16GB image & mount image - dd 8GB fileA - dd 8GB fileB - sync - rm fileA - sync - resize filesystem to 8GB kernel BUG at segment.c:2484! Call Trace: allocate_segment_by_default+0x92/0xf0 [f2fs] f2fs_allocate_data_block+0x44b/0x7e0 [f2fs] do_write_page+0x5a/0x110 [f2fs] f2fs_outplace_write_data+0x55/0x100 [f2fs] f2fs_do_write_data_page+0x392/0x850 [f2fs] move_data_page+0x233/0x320 [f2fs] do_garbage_collect+0x14d9/0x1660 [f2fs] free_segment_range+0x1f7/0x310 [f2fs] f2fs_resize_fs+0x118/0x330 [f2fs] __f2fs_ioctl+0x487/0x3680 [f2fs] __x64_sys_ioctl+0x8e/0xd0 do_syscall_64+0x33/0x80 entry_SYSCALL_64_after_hwframe+0x44/0xa9 The root cause is we forgot to check that whether we have enough space in resized filesystem to store all valid blocks in before-resizing filesystem, then allocator will run out-of-space during block migration in free_segment_range().

Category

5.5
CVSS
Severity: Medium
CVSS 3.1 •
EPSS 0.04%
Affected: Linux Linux
Affected: Linux Linux
Published at:
Updated at:

References

Link Tags
https://git.kernel.org/stable/c/1c20a4896409f5ca1c770e1880c33d0a28a8b10f patch
https://git.kernel.org/stable/c/860afd680d9cc1dabd61cda3cd246f60aa1eb705 patch
https://git.kernel.org/stable/c/822054e5026c43b1dd60cf387dd999e95ee2ecc2 patch
https://git.kernel.org/stable/c/3ab0598e6d860ef49d029943ba80f627c15c15d6 patch

Frequently Asked Questions

What is the severity of CVE-2021-47007?
CVE-2021-47007 has been scored as a medium severity vulnerability.
How to fix CVE-2021-47007?
To fix CVE-2021-47007, make sure you are using an up-to-date version of the affected component(s) by checking the vendor release notes. As for now, there are no other specific guidelines available.
Is CVE-2021-47007 being actively exploited in the wild?
As for now, there are no information to confirm that CVE-2021-47007 is being actively exploited. According to its EPSS score, there is a ~0% probability that this vulnerability will be exploited by malicious actors in the next 30 days.
What software or system is affected by CVE-2021-47007?
CVE-2021-47007 affects Linux Linux, Linux Linux.
This platform uses data from the NIST NVD, MITRE CVE, MITRE CWE, First.org and CISA KEV but is not endorsed or certified by these entities. CVE is a registred trademark of the MITRE Corporation and the authoritative source of CVE content is MITRE's CVE web site. CWE is a registred trademark of the MITRE Corporation and the authoritative source of CWE content is MITRE's CWE web site.
© 2025 Under My Watch. All Rights Reserved.