CVE-2024-42077

Published Jul 29, 2024

Last updated 7 months ago

Overview

Description
In the Linux kernel, the following vulnerability has been resolved: ocfs2: fix DIO failure due to insufficient transaction credits The code in ocfs2_dio_end_io_write() estimates number of necessary transaction credits using ocfs2_calc_extend_credits(). This however does not take into account that the IO could be arbitrarily large and can contain arbitrary number of extents. Extent tree manipulations do often extend the current transaction but not in all of the cases. For example if we have only single block extents in the tree, ocfs2_mark_extent_written() will end up calling ocfs2_replace_extent_rec() all the time and we will never extend the current transaction and eventually exhaust all the transaction credits if the IO contains many single block extents. Once that happens a WARN_ON(jbd2_handle_buffer_credits(handle) <= 0) is triggered in jbd2_journal_dirty_metadata() and subsequently OCFS2 aborts in response to this error. This was actually triggered by one of our customers on a heavily fragmented OCFS2 filesystem. To fix the issue make sure the transaction always has enough credits for one extent insert before each call of ocfs2_mark_extent_written(). Heming Zhao said: ------ PANIC: "Kernel panic - not syncing: OCFS2: (device dm-1): panic forced after error" PID: xxx TASK: xxxx CPU: 5 COMMAND: "SubmitThread-CA" #0 machine_kexec at ffffffff8c069932 #1 __crash_kexec at ffffffff8c1338fa #2 panic at ffffffff8c1d69b9 #3 ocfs2_handle_error at ffffffffc0c86c0c [ocfs2] #4 __ocfs2_abort at ffffffffc0c88387 [ocfs2] #5 ocfs2_journal_dirty at ffffffffc0c51e98 [ocfs2] #6 ocfs2_split_extent at ffffffffc0c27ea3 [ocfs2] #7 ocfs2_change_extent_flag at ffffffffc0c28053 [ocfs2] #8 ocfs2_mark_extent_written at ffffffffc0c28347 [ocfs2] #9 ocfs2_dio_end_io_write at ffffffffc0c2bef9 [ocfs2] #10 ocfs2_dio_end_io at ffffffffc0c2c0f5 [ocfs2] #11 dio_complete at ffffffff8c2b9fa7 #12 do_blockdev_direct_IO at ffffffff8c2bc09f #13 ocfs2_direct_IO at ffffffffc0c2b653 [ocfs2] #14 generic_file_direct_write at ffffffff8c1dcf14 #15 __generic_file_write_iter at ffffffff8c1dd07b #16 ocfs2_file_write_iter at ffffffffc0c49f1f [ocfs2] #17 aio_write at ffffffff8c2cc72e #18 kmem_cache_alloc at ffffffff8c248dde #19 do_io_submit at ffffffff8c2ccada #20 do_syscall_64 at ffffffff8c004984 #21 entry_SYSCALL_64_after_hwframe at ffffffff8c8000ba
Source
416baaa9-dc9f-4396-8d5f-8c081fb06d67
NVD status
Modified
Products
linux_kernel

Risk scores

CVSS 3.1

Type
Primary
Base score
5.5
Impact score
3.6
Exploitability score
1.8
Vector string
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Severity
MEDIUM

Weaknesses

nvd@nist.gov
NVD-CWE-noinfo

Social media

Hype score
Not currently trending

Configurations

  1. In the Linux kernel, the following vulnerability has been resolved: coresight: tmc-etr: Fix race condition between sysfs and perf mode When trying to run perf and sysfs mode simultaneously, the WARN_ON() in tmc_etr_enable_hw() is triggered sometimes: WARNING: CPU: 42 PID: 3911571 at drivers/hwtracing/coresight/coresight-tmc-etr.c:1060 tmc_etr_enable_hw+0xc0/0xd8 [coresight_tmc] [..snip..] Call trace: tmc_etr_enable_hw+0xc0/0xd8 [coresight_tmc] (P) tmc_enable_etr_sink+0x11c/0x250 [coresight_tmc] (L) tmc_enable_etr_sink+0x11c/0x250 [coresight_tmc] coresight_enable_path+0x1c8/0x218 [coresight] coresight_enable_sysfs+0xa4/0x228 [coresight] enable_source_store+0x58/0xa8 [coresight] dev_attr_store+0x20/0x40 sysfs_kf_write+0x4c/0x68 kernfs_fop_write_iter+0x120/0x1b8 vfs_write+0x2c8/0x388 ksys_write+0x74/0x108 __arm64_sys_write+0x24/0x38 el0_svc_common.constprop.0+0x64/0x148 do_el0_svc+0x24/0x38 el0_svc+0x3c/0x130 el0t_64_sync_handler+0xc8/0xd0 el0t_64_sync+0x1ac/0x1b0 ---[ end trace 0000000000000000 ]--- Since the enablement of sysfs mode is separeted into two critical regions, one for sysfs buffer allocation and another for hardware enablement, it's possible to race with the perf mode. Fix this by double check whether the perf mode's been used before enabling the hardware in sysfs mode. mode: [sysfs mode] [perf mode] tmc_etr_get_sysfs_buffer() spin_lock(&drvdata->spinlock) [sysfs buffer allocation] spin_unlock(&drvdata->spinlock) spin_lock(&drvdata->spinlock) tmc_etr_enable_hw() drvdata->etr_buf = etr_perf->etr_buf spin_unlock(&drvdata->spinlock) spin_lock(&drvdata->spinlock) tmc_etr_enable_hw() WARN_ON(drvdata->etr_buf) // WARN sicne etr_buf initialized at the perf side spin_unlock(&drvdata->spinlock) With this fix, we retain the check for CS_MODE_PERF in get_etr_sysfs_buf. This ensures we verify whether the perf mode's already running before we actually allocate the buffer. Then we can save the time of allocating/freeing the sysfs buffer if race with the perf mode.CVE-2026-46272