Re: [PATCH v19 10/11] tracing/wprobe: Support BTF typecast in fetchargs
flat view
From: sashiko-bot@kernel.org
Date: 2026-10-03 08:01:42
Also in:
linux-perf-users
From: Masami Hiramatsu (Google) <mhiramat@kernel.org> Allow BTF typecast syntax (STRUCT)FETCHARG->MEMBER in wprobe event fetchargs. Previously, handle_typecast() rejected any probe context that was not a function entry/return or tracepoint event probe. Wprobe events use $addr (the accessed address) and $value (the value at that address). By enabling BTF typecast, users can now cast these to a concrete struct type and access its fields directly. For example: echo 'w:watch rw@-1:8 dflag=(dentry)$addr->d_flags' >> dynamic_events With a set_wprobe trigger pointing the watchpoint at a dentry address, the resulting trace shows d_flags being accessed at that location. Note that $addr and $value are restricted to kernel-space memory, which is consistent with the existing TPARG_FL_KERNEL flag used when parsing wprobe fetchargs. Assisted-by: LLM Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Sashiko has reviewed this patch and found no issues. It looks great! -- Sashiko AI review · https://sashiko.dev/#/patchset/179101393469.22872.5895666191299551553.stgit@devnote2?part=10