CVE-2024-56743

/// Technical description

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

nfs_common: must not hold RCU while calling nfsd_file_put_local

Move holding the RCU from nfs_to_nfsd_file_put_local to

nfs_to_nfsd_net_put. It is the call to nfs_to->nfsd_serv_put that

requires the RCU anyway (the puts for nfsd_file and netns were

combined to avoid an extra indirect reference but that

micro-optimization isn't possible now).

This fixes xfstests generic/013 and it triggering:

"Voluntary context switch within RCU read-side critical section!"

[ 143.545738] Call Trace:

[ 143.546206] <TASK>

[ 143.546625] ? show_regs+0x6d/0x80

[ 143.547267] ? __warn+0x91/0x140

[ 143.547951] ? rcu_note_context_switch+0x496/0x5d0

[ 143.548856] ? report_bug+0x193/0x1a0

[ 143.549557] ? handle_bug+0x63/0xa0

[ 143.550214] ? exc_invalid_op+0x1d/0x80

[ 143.550938] ? asm_exc_invalid_op+0x1f/0x30

[ 143.551736] ? rcu_note_context_switch+0x496/0x5d0

[ 143.552634] ? wakeup_preempt+0x62/0x70

[ 143.553358] __sc

/// Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

/// References