While testing ipcomp on a realtime kernel, Xiumei reported a "sleeping in atomic" bug, caused by a memory allocation while preemption is disabled (ipcomp_decompress -> alloc_page -> ... get_page_from_freelist). As Sebastian noted [1], this get_cpu() isn't actually needed, since ipcomp_decompress() is called in napi context anyway, so BH is already disabled. This patch replaces get_cpu + per_cpu_ptr with this_cpu_ptr, then simplifies the error returns, since there isn't any common operation left. [1] https://lore.kernel.org/lkml/20190820082810.ixkmi56fp7u7eyn2@linutronix.de/ Cc: Juri Lelli <jlelli@redhat.com> Reported-by: Xiumei Mu <xmu@redhat.com> Suggested-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Signed-off-by: Sabrina Dubroca <sd@queasysnail.net> Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
Linux kernel ============ There are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. Please read Documentation/admin-guide/README.rst first. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. The formatted documentation can also be read online at: https://www.kernel.org/doc/html/latest/ There are various text files in the Documentation/ subdirectory, several of them using the Restructured Text markup notation. 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.
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