Commit cb7d761b authored Jan 16, 2026 by Suren Baghdasaryan Committed by Andrew Morton Jan 20, 2026

Docs/mm/allocation-profiling: describe sysctrl limitations in debug mode

When CONFIG_MEM_ALLOC_PROFILING_DEBUG=y, /proc/sys/vm/mem_profiling is
read-only to avoid debug warnings in a scenario when an allocation is
made while profiling is disabled (allocation does not get an allocation
tag), then profiling gets enabled and allocation gets freed (warning due
to the allocation missing allocation tag).

Link: https://lkml.kernel.org/r/20260116184423.2708363-1-surenb@google.com


Fixes: ebdf9ad4 ("memprofiling: documentation")
Reported-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Suren Baghdasaryan <surenb@google.com>
Acked-by: SeongJae Park <sj@kernel.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Kent Overstreet <kent.overstreet@linux.dev>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Ran Xiaokai <ran.xiaokai@zte.com.cn>
Cc: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

parent 35e24703

Documentation/admin-guide/sysctl/vm.rst

+4 −0

Original line number	Diff line number	Diff line
		@@ -494,6 +494,10 @@ memory allocations.

		The default value depends on CONFIG_MEM_ALLOC_PROFILING_ENABLED_BY_DEFAULT.

		When CONFIG_MEM_ALLOC_PROFILING_DEBUG=y, this control is read-only to avoid
		warnings produced by allocations made while profiling is disabled and freed
		when it's enabled.


		memory_failure_early_kill
		=========================

Documentation/mm/allocation-profiling.rst

+10 −0

Original line number	Diff line number	Diff line
		@@ -33,6 +33,16 @@ Boot parameter:
		sysctl:
		/proc/sys/vm/mem_profiling

		1: Enable memory profiling.

		0: Disable memory profiling.

		The default value depends on CONFIG_MEM_ALLOC_PROFILING_ENABLED_BY_DEFAULT.

		When CONFIG_MEM_ALLOC_PROFILING_DEBUG=y, this control is read-only to avoid
		warnings produced by allocations made while profiling is disabled and freed
		when it's enabled.

		Runtime info:
		/proc/allocinfo