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FROMGIT: mm/cma.c: delete kmemleak objects when freeing CMA areas to buddy at boot

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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>

Bug: 265065728
(cherry picked from commit 7612fee153e571473ad266ae9109b7a2fea35f56
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm.git mm-unstable)
Change-Id: Ifd0ed91d9381ca38b5d9200d52a71e356544596e
Signed-off-by: Isaac J. Manjarres <isaacmanjarres@google.com>
This commit is contained in:
Isaac J. Manjarres
2023-01-09 14:16:23 -08:00
parent e51492910c
commit 6d9e986186
1 changed files with 7 additions and 5 deletions
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12
mm/cma.c
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@@ -111,6 +111,13 @@ static void __init cma_activate_area(struct cma *cma)
if (!cma->bitmap)
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
@@ -373,11 +380,6 @@ int __init cma_declare_contiguous_nid(phys_addr_t base,
}
}
/*
* kmemleak scans/reads tracked objects for pointers to other
* objects but this address isn't mapped and accessible
*/
kmemleak_ignore_phys(addr);
base = addr;
}