CVE-2022-49782

/// Technical description

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

perf: Improve missing SIGTRAP checking

To catch missing SIGTRAP we employ a WARN in __perf_event_overflow(),

which fires if pending_sigtrap was already set: returning to user space

without consuming pending_sigtrap, and then having the event fire again

would re-enter the kernel and trigger the WARN.

This, however, seemed to miss the case where some events not associated

with progress in the user space task can fire and the interrupt handler

runs before the IRQ work meant to consume pending_sigtrap (and generate

the SIGTRAP).

syzbot gifted us this stack trace:

| WARNING: CPU: 0 PID: 3607 at kernel/events/core.c:9313 __perf_event_overflow

| Modules linked in:

| CPU: 0 PID: 3607 Comm: syz-executor100 Not tainted 6.1.0-rc2-syzkaller-00073-g88619e77b33d #0

| Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/11/2022

| RIP: 0010:__perf_event_overflow+0x498/0x540 kernel/events/core.c:9

/// 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