+ alloc_tag-handle-incomplete-bulk-allocations-in-vm_module_tags_populate.patch added to mm-hotfixes-unstable branch
The patch titled Subject: alloc_tag: handle incomplete bulk allocations in vm_module_tags_populate has been added to the -mm mm-hotfixes-unstable branch. Its filename is alloc_tag-handle-incomplete-bulk-allocations-in-vm_module_tags_populate.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-hotfixes-unstable branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's
*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***
The -mm tree is included into linux-next via the mm-everything branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm and is updated there every 2-3 working days
------------------------------------------------------ From: "T.J. Mercier" tjmercier@google.com Subject: alloc_tag: handle incomplete bulk allocations in vm_module_tags_populate Date: Wed, 9 Apr 2025 19:54:47 +0000
alloc_pages_bulk_node may partially succeed and allocate fewer than the requested nr_pages. There are several conditions under which this can occur, but we have encountered the case where CONFIG_PAGE_OWNER is enabled causing all bulk allocations to always fallback to single page allocations due to commit 187ad460b841 ("mm/page_alloc: avoid page allocator recursion with pagesets.lock held").
Currently vm_module_tags_populate immediately fails when alloc_pages_bulk_node returns fewer than the requested number of pages. This patch causes vm_module_tags_populate to retry bulk allocations for the remaining memory instead.
Link: https://lkml.kernel.org/r/20250409195448.3697351-1-tjmercier@google.com Fixes: 187ad460b841 ("mm/page_alloc: avoid page allocator recursion with pagesets.lock held") Signed-off-by: T.J. Mercier tjmercier@google.com Reported-by: Janghyuck Kim janghyuck.kim@samsung.com Cc: Kent Overstreet kent.overstreet@linux.dev Cc: Suren Baghdasaryan surenb@google.com Cc: stable@vger.kernel.org Signed-off-by: Andrew Morton akpm@linux-foundation.org ---
lib/alloc_tag.c | 15 ++++++++++++--- 1 file changed, 12 insertions(+), 3 deletions(-)
--- a/lib/alloc_tag.c~alloc_tag-handle-incomplete-bulk-allocations-in-vm_module_tags_populate +++ a/lib/alloc_tag.c @@ -422,11 +422,20 @@ static int vm_module_tags_populate(void) unsigned long old_shadow_end = ALIGN(phys_end, MODULE_ALIGN); unsigned long new_shadow_end = ALIGN(new_end, MODULE_ALIGN); unsigned long more_pages; - unsigned long nr; + unsigned long nr = 0;
more_pages = ALIGN(new_end - phys_end, PAGE_SIZE) >> PAGE_SHIFT; - nr = alloc_pages_bulk_node(GFP_KERNEL | __GFP_NOWARN, - NUMA_NO_NODE, more_pages, next_page); + while (nr < more_pages) { + unsigned long allocated; + + allocated = alloc_pages_bulk_node(GFP_KERNEL | __GFP_NOWARN, + NUMA_NO_NODE, more_pages - nr, next_page + nr); + + if (!allocated) + break; + nr += allocated; + } + if (nr < more_pages || vmap_pages_range(phys_end, phys_end + (nr << PAGE_SHIFT), PAGE_KERNEL, next_page, PAGE_SHIFT) < 0) { _
Patches currently in -mm which might be from tjmercier@google.com are
alloc_tag-handle-incomplete-bulk-allocations-in-vm_module_tags_populate.patch
On Wed, Apr 9, 2025 at 2:12 PM Andrew Morton akpm@linux-foundation.org wrote:
The patch titled Subject: alloc_tag: handle incomplete bulk allocations in vm_module_tags_populate has been added to the -mm mm-hotfixes-unstable branch. Its filename is alloc_tag-handle-incomplete-bulk-allocations-in-vm_module_tags_populate.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-hotfixes-unstable branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's
*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***
The -mm tree is included into linux-next via the mm-everything branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm and is updated there every 2-3 working days
From: "T.J. Mercier" tjmercier@google.com Subject: alloc_tag: handle incomplete bulk allocations in vm_module_tags_populate Date: Wed, 9 Apr 2025 19:54:47 +0000
alloc_pages_bulk_node may partially succeed and allocate fewer than the requested nr_pages. There are several conditions under which this can occur, but we have encountered the case where CONFIG_PAGE_OWNER is enabled causing all bulk allocations to always fallback to single page allocations due to commit 187ad460b841 ("mm/page_alloc: avoid page allocator recursion with pagesets.lock held").
Currently vm_module_tags_populate immediately fails when alloc_pages_bulk_node returns fewer than the requested number of pages. This patch causes vm_module_tags_populate to retry bulk allocations for the remaining memory instead.
Link: https://lkml.kernel.org/r/20250409195448.3697351-1-tjmercier@google.com Fixes: 187ad460b841 ("mm/page_alloc: avoid page allocator recursion with pagesets.lock held")
I wasn't sure if this should have a Fixes: but since allocation tags came after the commit above, I think it'd be better to reference 0f9b685626da ("alloc_tag: populate memory for module tags as needed") which introduced this bulk allocation.
Signed-off-by: T.J. Mercier tjmercier@google.com Reported-by: Janghyuck Kim janghyuck.kim@samsung.com Cc: Kent Overstreet kent.overstreet@linux.dev Cc: Suren Baghdasaryan surenb@google.com Cc: stable@vger.kernel.org Signed-off-by: Andrew Morton akpm@linux-foundation.org
lib/alloc_tag.c | 15 ++++++++++++--- 1 file changed, 12 insertions(+), 3 deletions(-)
--- a/lib/alloc_tag.c~alloc_tag-handle-incomplete-bulk-allocations-in-vm_module_tags_populate +++ a/lib/alloc_tag.c @@ -422,11 +422,20 @@ static int vm_module_tags_populate(void) unsigned long old_shadow_end = ALIGN(phys_end, MODULE_ALIGN); unsigned long new_shadow_end = ALIGN(new_end, MODULE_ALIGN); unsigned long more_pages;
unsigned long nr;
unsigned long nr = 0; more_pages = ALIGN(new_end - phys_end, PAGE_SIZE) >> PAGE_SHIFT;
nr = alloc_pages_bulk_node(GFP_KERNEL | __GFP_NOWARN,NUMA_NO_NODE, more_pages, next_page);
while (nr < more_pages) {unsigned long allocated;allocated = alloc_pages_bulk_node(GFP_KERNEL | __GFP_NOWARN,NUMA_NO_NODE, more_pages - nr, next_page + nr);if (!allocated)break;nr += allocated;}if (nr < more_pages || vmap_pages_range(phys_end, phys_end + (nr << PAGE_SHIFT), PAGE_KERNEL, next_page, PAGE_SHIFT) < 0) {_
Patches currently in -mm which might be from tjmercier@google.com are
alloc_tag-handle-incomplete-bulk-allocations-in-vm_module_tags_populate.patch
On Wed, Apr 09, 2025 at 02:12:40PM -0700, Andrew Morton wrote:
The patch titled Subject: alloc_tag: handle incomplete bulk allocations in vm_module_tags_populate has been added to the -mm mm-hotfixes-unstable branch. Its filename is alloc_tag-handle-incomplete-bulk-allocations-in-vm_module_tags_populate.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-hotfixes-unstable branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's
*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***
The -mm tree is included into linux-next via the mm-everything branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm and is updated there every 2-3 working days
I don't think we want to rush this patch, given that it's not fixing an actual crash.
I'm currently chasing a crash (null ptr deref, slab obj extension vector seems to not be getting allocated correctly) in 6.15-rc1, so I'm wondering what's missing in our test coverage.
From: "T.J. Mercier" tjmercier@google.com Subject: alloc_tag: handle incomplete bulk allocations in vm_module_tags_populate Date: Wed, 9 Apr 2025 19:54:47 +0000
alloc_pages_bulk_node may partially succeed and allocate fewer than the requested nr_pages. There are several conditions under which this can occur, but we have encountered the case where CONFIG_PAGE_OWNER is enabled causing all bulk allocations to always fallback to single page allocations due to commit 187ad460b841 ("mm/page_alloc: avoid page allocator recursion with pagesets.lock held").
Currently vm_module_tags_populate immediately fails when alloc_pages_bulk_node returns fewer than the requested number of pages. This patch causes vm_module_tags_populate to retry bulk allocations for the remaining memory instead.
Link: https://lkml.kernel.org/r/20250409195448.3697351-1-tjmercier@google.com Fixes: 187ad460b841 ("mm/page_alloc: avoid page allocator recursion with pagesets.lock held") Signed-off-by: T.J. Mercier tjmercier@google.com Reported-by: Janghyuck Kim janghyuck.kim@samsung.com Cc: Kent Overstreet kent.overstreet@linux.dev Cc: Suren Baghdasaryan surenb@google.com Cc: stable@vger.kernel.org Signed-off-by: Andrew Morton akpm@linux-foundation.org
lib/alloc_tag.c | 15 ++++++++++++--- 1 file changed, 12 insertions(+), 3 deletions(-)
--- a/lib/alloc_tag.c~alloc_tag-handle-incomplete-bulk-allocations-in-vm_module_tags_populate +++ a/lib/alloc_tag.c @@ -422,11 +422,20 @@ static int vm_module_tags_populate(void) unsigned long old_shadow_end = ALIGN(phys_end, MODULE_ALIGN); unsigned long new_shadow_end = ALIGN(new_end, MODULE_ALIGN); unsigned long more_pages;
unsigned long nr;
unsigned long nr = 0;more_pages = ALIGN(new_end - phys_end, PAGE_SIZE) >> PAGE_SHIFT;
nr = alloc_pages_bulk_node(GFP_KERNEL | __GFP_NOWARN,NUMA_NO_NODE, more_pages, next_page);
while (nr < more_pages) {unsigned long allocated;allocated = alloc_pages_bulk_node(GFP_KERNEL | __GFP_NOWARN,NUMA_NO_NODE, more_pages - nr, next_page + nr);if (!allocated)break;nr += allocated;}- if (nr < more_pages || vmap_pages_range(phys_end, phys_end + (nr << PAGE_SHIFT), PAGE_KERNEL, next_page, PAGE_SHIFT) < 0) {
_
Patches currently in -mm which might be from tjmercier@google.com are
alloc_tag-handle-incomplete-bulk-allocations-in-vm_module_tags_populate.patch
On Wed, Apr 9, 2025 at 3:10 PM Kent Overstreet kent.overstreet@linux.dev wrote:
On Wed, Apr 09, 2025 at 02:12:40PM -0700, Andrew Morton wrote:
The patch titled Subject: alloc_tag: handle incomplete bulk allocations in vm_module_tags_populate has been added to the -mm mm-hotfixes-unstable branch. Its filename is alloc_tag-handle-incomplete-bulk-allocations-in-vm_module_tags_populate.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-hotfixes-unstable branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's
*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***
The -mm tree is included into linux-next via the mm-everything branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm and is updated there every 2-3 working days
I don't think we want to rush this patch, given that it's not fixing an actual crash.
It's not designed to fix a crash. The issue is that whenever tags require more than one page and CONFIG_PAGE_OWNER is enabled, memory allocation profiling gets disabled. I missed the fact that alloc_pages_bulk_node() can return less number of pages than requested and this patch fixes that.
I'm currently chasing a crash (null ptr deref, slab obj extension vector seems to not be getting allocated correctly) in 6.15-rc1, so I'm wondering what's missing in our test coverage.
From: "T.J. Mercier" tjmercier@google.com Subject: alloc_tag: handle incomplete bulk allocations in vm_module_tags_populate Date: Wed, 9 Apr 2025 19:54:47 +0000
alloc_pages_bulk_node may partially succeed and allocate fewer than the requested nr_pages. There are several conditions under which this can occur, but we have encountered the case where CONFIG_PAGE_OWNER is enabled causing all bulk allocations to always fallback to single page allocations due to commit 187ad460b841 ("mm/page_alloc: avoid page allocator recursion with pagesets.lock held").
Currently vm_module_tags_populate immediately fails when alloc_pages_bulk_node returns fewer than the requested number of pages. This patch causes vm_module_tags_populate to retry bulk allocations for the remaining memory instead.
Link: https://lkml.kernel.org/r/20250409195448.3697351-1-tjmercier@google.com Fixes: 187ad460b841 ("mm/page_alloc: avoid page allocator recursion with pagesets.lock held") Signed-off-by: T.J. Mercier tjmercier@google.com Reported-by: Janghyuck Kim janghyuck.kim@samsung.com Cc: Kent Overstreet kent.overstreet@linux.dev Cc: Suren Baghdasaryan surenb@google.com Cc: stable@vger.kernel.org Signed-off-by: Andrew Morton akpm@linux-foundation.org
lib/alloc_tag.c | 15 ++++++++++++--- 1 file changed, 12 insertions(+), 3 deletions(-)
--- a/lib/alloc_tag.c~alloc_tag-handle-incomplete-bulk-allocations-in-vm_module_tags_populate +++ a/lib/alloc_tag.c @@ -422,11 +422,20 @@ static int vm_module_tags_populate(void) unsigned long old_shadow_end = ALIGN(phys_end, MODULE_ALIGN); unsigned long new_shadow_end = ALIGN(new_end, MODULE_ALIGN); unsigned long more_pages;
unsigned long nr;
unsigned long nr = 0; more_pages = ALIGN(new_end - phys_end, PAGE_SIZE) >> PAGE_SHIFT;
nr = alloc_pages_bulk_node(GFP_KERNEL | __GFP_NOWARN,NUMA_NO_NODE, more_pages, next_page);
while (nr < more_pages) {unsigned long allocated;allocated = alloc_pages_bulk_node(GFP_KERNEL | __GFP_NOWARN,NUMA_NO_NODE, more_pages - nr, next_page + nr);if (!allocated)break;nr += allocated;}if (nr < more_pages || vmap_pages_range(phys_end, phys_end + (nr << PAGE_SHIFT), PAGE_KERNEL, next_page, PAGE_SHIFT) < 0) {_
Patches currently in -mm which might be from tjmercier@google.com are
alloc_tag-handle-incomplete-bulk-allocations-in-vm_module_tags_populate.patch
On Wed, Apr 09, 2025 at 03:31:57PM -0700, Suren Baghdasaryan wrote:
On Wed, Apr 9, 2025 at 3:10 PM Kent Overstreet kent.overstreet@linux.dev wrote:
On Wed, Apr 09, 2025 at 02:12:40PM -0700, Andrew Morton wrote:
The patch titled Subject: alloc_tag: handle incomplete bulk allocations in vm_module_tags_populate has been added to the -mm mm-hotfixes-unstable branch. Its filename is alloc_tag-handle-incomplete-bulk-allocations-in-vm_module_tags_populate.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-hotfixes-unstable branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's
*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***
The -mm tree is included into linux-next via the mm-everything branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm and is updated there every 2-3 working days
I don't think we want to rush this patch, given that it's not fixing an actual crash.
It's not designed to fix a crash. The issue is that whenever tags require more than one page and CONFIG_PAGE_OWNER is enabled, memory allocation profiling gets disabled. I missed the fact that alloc_pages_bulk_node() can return less number of pages than requested and this patch fixes that.
That's my point; "allocation profiling gets silently disabled" is much less severe than the crash we're chasing.
I just want to make sure we're not introducing new things while we're chasing more severe bugs, although the patch does look simple enough.
linux-stable-mirror@lists.linaro.org
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Andrew Morton -
Kent Overstreet -
Suren Baghdasaryan -
T.J. Mercier