The patch titled Subject: mm/cma.c: delete kmemleak objects when freeing CMA areas to buddy at boot has been added to the -mm mm-unstable branch. Its filename is mm-cmac-delete-kmemleak-objects-when-freeing-cma-areas-to-buddy-at-boot.patch

This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches...

This patch will later appear in the mm-unstable branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

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------------------------------------------------------ From: "Isaac J. Manjarres" isaacmanjarres@google.com Subject: mm/cma.c: delete kmemleak objects when freeing CMA areas to buddy at boot Date: Mon, 9 Jan 2023 14:16:23 -0800

Since every CMA region is now tracked by kmemleak at the time cma_activate_area() is invoked, and cma_activate_area() is called for each CMA region, invoke kmemleak_free_part_phys() during cma_activate_area() to inform kmemleak that the CMA region will be freed. Doing so also removes the need to invoke kmemleak_ignore_phys() when the global CMA region is being created, as the kmemleak object for it will be deleted.

This helps resolve a crash when kmemleak and CONFIG_DEBUG_PAGEALLOC are both enabled, since CONFIG_DEBUG_PAGEALLOC causes the CMA region to be unmapped from the kernel's address space when the pages are freed to buddy. Without this patch, kmemleak will attempt to scan the CMA regions, even though they are unmapped, which leads to a page-fault.

Link: https://lkml.kernel.org/r/20230109221624.592315-3-isaacmanjarres@google.com Signed-off-by: Isaac J. Manjarres isaacmanjarres@google.com Cc: Isaac J. Manjarres isaacmanjarres@google.com Cc: Saravana Kannan saravanak@google.com Cc: Suren Baghdasaryan surenb@google.com Cc: Catalin Marinas catalin.marinas@arm.com Cc: stable@vger.kernel.org Signed-off-by: Andrew Morton akpm@linux-foundation.org ---

mm/cma.c | 12 +++++++----- 1 file changed, 7 insertions(+), 5 deletions(-)

--- a/mm/cma.c~mm-cmac-delete-kmemleak-objects-when-freeing-cma-areas-to-buddy-at-boot +++ a/mm/cma.c @@ -103,6 +103,13 @@ static void __init cma_activate_area(str goto out_error;

/* + * The CMA region was marked as allocated by kmemleak when it was either + * dynamically allocated or statically reserved. In any case, + * inform kmemleak that the region is about to be freed to the page allocator. + */ + kmemleak_free_part_phys(cma_get_base(cma), cma_get_size(cma)); + + /* * alloc_contig_range() requires the pfn range specified to be in the * same zone. Simplify by forcing the entire CMA resv range to be in the * same zone. @@ -361,11 +368,6 @@ int __init cma_declare_contiguous_nid(ph } }

- /* - * kmemleak scans/reads tracked objects for pointers to other - * objects but this address isn't mapped and accessible - */ - kmemleak_ignore_phys(addr); base = addr; }

_

Patches currently in -mm which might be from isaacmanjarres@google.com are

mm-cmac-make-kmemleak-aware-of-all-cma-regions.patch mm-cmac-delete-kmemleak-objects-when-freeing-cma-areas-to-buddy-at-boot.patch