CVE-2024-50132: NULL Pointer Dereference

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

tracing/probes: Fix MAX_TRACE_ARGS limit handling

When creating a trace_probe we would set nr_args prior to truncating the arguments to MAX_TRACE_ARGS. However, we would only initialize arguments up to the limit.

This caused invalid memory access when attempting to set up probes with more than 128 fetchargs.

BUG: kernel NULL pointer dereference, address: 0000000000000020 #PF: supervisor read access in kernel mode #PF: error_code(0x0000) - not-present page PGD 0 P4D 0 Oops: Oops: 0000 [#1] PREEMPT SMP PTI CPU: 0 UID: 0 PID: 1769 Comm: cat Not tainted 6.11.0-rc7+ #8 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.3-1.fc39 04/01/2014 RIP: 0010:__set_print_fmt+0x134/0x330

Resolve the issue by applying the MAX_TRACE_ARGS limit earlier. Return an error when there are too many arguments instead of silently truncating.