CVE-2023-54023In the Linux kernel, the following vulnerability has been resolved: btrfs: fix race between balance and cancel/pause Syzbot reported a panic that looks like this: assertion failed: fs_info->exclusive…

In the Linux kernel, the following vulnerability has been resolved: btrfs: fix race between balance and cancel/pause Syzbot reported a panic that looks like this: assertion failed: fs_info->exclusive_operation == BTRFS_EXCLOP_BALANCE_PAUSED, in fs/btrfs/ioctl.c:465 ------------[ cut here ]------------ kernel BUG at fs/btrfs/messages.c:259! RIP: 0010:btrfs_assertfail+0x2c/0x30 fs/btrfs/messages.c:259 Call Trace: <TASK> btrfs_exclop_balance fs/btrfs/ioctl.c:465 [inline] btrfs_ioctl_balance fs/btrfs/ioctl.c:3564 [inline] btrfs_ioctl+0x531e/0x5b30 fs/btrfs/ioctl.c:4632 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:870 [inline] __se_sys_ioctl fs/ioctl.c:856 [inline] __x64_sys_ioctl+0x197/0x210 fs/ioctl.c:856 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd The reproducer is running a balance and a cancel or pause in parallel. The way balance finishes is a bit wonky, if we were paused we need to save the balance_ctl in the fs_info, but clear it otherwise and cleanup. However we rely on the return values being specific errors, or having a cancel request or no pause request. If balance completes and returns 0, but we have a pause or cancel request we won't do the appropriate cleanup, and then the next time we try to start a balance we'll trip this ASSERT. The error handling is just wrong here, we always want to clean up, unless we got -ECANCELLED and we set the appropriate pause flag in the exclusive op. With this patch the reproducer ran for an hour without tripping, previously it would trip in less than a few minutes.

CVSS

Not yet scored

Weakness (CWE)

Not given

Known exploited

Not in CISA's KEV catalog

EPSS (exploitation in the next 30 days)

Not loaded for this CVE

Assigned by

Not given

NVD analysis

Deferred

Record last updated

Jun 17, 2026

First seen by InfoSec Signals

Oct 9, 2026

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