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Currently, we cannot parse build_id in nmi context because of up_read(¤t->mm->mmap_sem), this makes stackmap with build_id less useful. This patch enables parsing build_id in nmi by putting the up_read() call in irq_work. To avoid memory allocation in nmi context, we use per cpu variable for the irq_work. As a result, only one irq_work per cpu is allowed. If the irq_work is in-use, we fallback to only report ips. Cc: Alexei Starovoitov <ast@kernel.org> Cc: Daniel Borkmann <daniel@iogearbox.net> Cc: Peter Zijlstra <peterz@infradead.org> Change-Id: I482218bf334ff9486b1c43db0105a6de5e0b1de6 Signed-off-by: Song Liu <songliubraving@fb.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Linux kernel ============ This file was moved to Documentation/admin-guide/README.rst Please notice that there are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. There are various text files in the Documentation/ subdirectory, several of them using the Restructured Text markup notation. See Documentation/00-INDEX for a list of what is contained in each file. Please read the Documentation/process/changes.rst file, as it contains the requirements for building and running the kernel, and information about the problems which may result by upgrading your kernel.