Messages in this thread Patch in this message | | | Date | Wed, 8 May 2013 15:09:32 -0700 | From | Andrew Morton <> | Subject | Re: [PATCH] Fix crash during slab init |
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On Wed, 8 May 2013 15:56:28 -0400 Chris Mason <clmason@fusionio.com> wrote:
> Commit 8a965b3b introduced a regression that caused us to crash early > during boot. The commit was introducing ordering of slab creation, > making sure two odd-sized slabs were created after specific powers of > two sizes. > > But, if any of the power of two slabs were created earlier during boot, > slabs at index 1 or 2 might not get created at all. This patch makes > sure none of the slabs get skipped. > > Tony Lindgren bisected this down to the offending commit, which really > helped because bisect kept bringing me to almost but not quite this one.
err, yes. Without your patch, current mainline does an ignominious faceplant on my test box.
From: Chris Mason <clmason@fusionio.com> Subject: slab: fix crash during slab init
Commit 8a965b3b ("mm, slab_common: Fix bootstrap creation of kmalloc caches") introduced a regression that caused us to crash early during boot. The commit was introducing ordering of slab creation, making sure two odd-sized slabs were created after specific powers of two sizes.
But, if any of the power of two slabs were created earlier during boot, slabs at index 1 or 2 might not get created at all. This patch makes sure none of the slabs get skipped.
Tony Lindgren bisected this down to the offending commit, which really helped because bisect kept bringing me to almost but not quite this one.
Signed-off-by: Chris Mason <chris.mason@fusionio.com> Acked-by: Christoph Lameter <cl@linux.com> Acked-by: Tony Lindgren <tony@atomide.com> Tested-by: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp> Cc: Pekka Enberg <penberg@kernel.org> Tested-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> ---
mm/slab_common.c | 20 ++++++++++---------- 1 file changed, 10 insertions(+), 10 deletions(-)
diff -puN mm/slab_common.c~slab-fix-crash-during-slab-init mm/slab_common.c --- a/mm/slab_common.c~slab-fix-crash-during-slab-init +++ a/mm/slab_common.c @@ -446,18 +446,18 @@ void __init create_kmalloc_caches(unsign if (!kmalloc_caches[i]) { kmalloc_caches[i] = create_kmalloc_cache(NULL, 1 << i, flags); + } - /* - * Caches that are not of the two-to-the-power-of size. - * These have to be created immediately after the - * earlier power of two caches - */ - if (KMALLOC_MIN_SIZE <= 32 && !kmalloc_caches[1] && i == 6) - kmalloc_caches[1] = create_kmalloc_cache(NULL, 96, flags); + /* + * Caches that are not of the two-to-the-power-of size. + * These have to be created immediately after the + * earlier power of two caches + */ + if (KMALLOC_MIN_SIZE <= 32 && !kmalloc_caches[1] && i == 6) + kmalloc_caches[1] = create_kmalloc_cache(NULL, 96, flags); - if (KMALLOC_MIN_SIZE <= 64 && !kmalloc_caches[2] && i == 7) - kmalloc_caches[2] = create_kmalloc_cache(NULL, 192, flags); - } + if (KMALLOC_MIN_SIZE <= 64 && !kmalloc_caches[2] && i == 7) + kmalloc_caches[2] = create_kmalloc_cache(NULL, 192, flags); } /* Kmalloc array is now usable */ _
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