From: sashiko-bot@kernel.org
To: "Mike Rapoport (Microsoft)" <rppt@kernel.org>
Cc: "Heiko Carstens" <hca@linux.ibm.com>,
"Vasily Gorbik" <gor@linux.ibm.com>,
"Alexander Gordeev" <agordeev@linux.ibm.com>,
linux-s390@vger.kernel.org,
"Christian Borntraeger" <borntraeger@linux.ibm.com>
Subject: Re: [PATCH 2/6] mm/vmalloc: set area's page_order after allocation succeeds
Date: Sun, 16 Aug 2026 11:08:42 +0000 [thread overview]
Message-ID: <20260816110843.3FF251F000E9@smtp.kernel.org> (raw)
In-Reply-To: <20260816-execmem-set-vm-perms-v0-2-v1-2-90944a3ad43f@kernel.org>
> __vmalloc_area_node() calls set_vm_area_page_order() to set area's
> page_order before actually allocating pages to populate the area.
>
> If allocation of large pages in HUGE_VMAP case fails midway, this leaves
> the area with elevated page_order throughout the cleanup path.
>
> There is no actual issue with this because the only place that currently
> relies on area->page_order on the cleanup path is the loop calculating
> the direct map alias range in vm_reset_perms() and it anyway skips
> unpopulated pages.
>
> But having set_vm_area_page_order() in the middle of __vmalloc_area_node()
> makes things very obscure, hard to reason about and error prone against
> future changes of the cleanup path.
>
> Move the call to set_vm_area_page_order() after __vmalloc_area_node()
> succeeded where page order is guaranteed.
>
> Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Sashiko has reviewed this patch and found no issues. It looks great!
--
Sashiko AI review · https://sashiko.dev/#/patchset/20260816-execmem-set-vm-perms-v0-2-v1-0-90944a3ad43f@kernel.org?part=2
next prev parent reply other threads:[~2026-08-16 11:08 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-08-16 10:59 [PATCH 0/6] arch, mm/execmem: resolve confusion about set_direct_map_valid_noflush() Mike Rapoport (Microsoft)
2026-08-16 10:59 ` [PATCH 1/6] set_memory: add number of pages parameter to set_direct_map APIs Mike Rapoport (Microsoft)
2026-08-16 11:12 ` sashiko-bot
2026-08-16 10:59 ` [PATCH 2/6] mm/vmalloc: set area's page_order after allocation succeeds Mike Rapoport (Microsoft)
2026-08-16 11:08 ` sashiko-bot [this message]
2026-08-16 10:59 ` [PATCH 3/6] mm/vmalloc: constify vm parameter of get_vm_area_page_order() Mike Rapoport (Microsoft)
2026-08-16 11:03 ` sashiko-bot
2026-08-16 10:59 ` [PATCH 4/6] mm/vmalloc: make set_area_direct_map HUGE_VMAP friendly Mike Rapoport (Microsoft)
2026-08-16 11:10 ` sashiko-bot
2026-08-16 10:59 ` [PATCH 5/6] mm/execmem: use VM_FLUSH_RESET_PERMS for ROX cache allocations Mike Rapoport (Microsoft)
2026-08-16 11:17 ` sashiko-bot
2026-08-16 10:59 ` [PATCH 6/6] Revert "arch: introduce set_direct_map_valid_noflush()" Mike Rapoport (Microsoft)
2026-08-16 11:03 ` sashiko-bot
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