lkml.org 
[lkml]   [2023]   [Sep]   [6]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
From
Date
SubjectRe: [merged mm-hotfixes-stable] mm-vmalloc-add-a-safer-version-of-find_vm_area-for-debug.patch removed from -mm tree
On Wed, 6 Sept 2023 at 16:09, Andrew Morton <akpm@linux-foundation.org> wrote:
>
>
> The quilt patch titled
> Subject: mm/vmalloc: add a safer version of find_vm_area() for debug
> has been removed from the -mm tree. Its filename was
> mm-vmalloc-add-a-safer-version-of-find_vm_area-for-debug.patch
>
> This patch was dropped because it was merged into the mm-hotfixes-stable branch
> of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

Hmm, I had outstanding review on this :/ I guess I will have to send a
follow up patch to address those concerns...


>
> ------------------------------------------------------
> From: "Joel Fernandes (Google)" <joel@joelfernandes.org>
> Subject: mm/vmalloc: add a safer version of find_vm_area() for debug
> Date: Mon, 4 Sep 2023 18:08:04 +0000
>
> It is unsafe to dump vmalloc area information when trying to do so from
> some contexts. Add a safer trylock version of the same function to do a
> best-effort VMA finding and use it from vmalloc_dump_obj().
>
> [applied test robot feedback on unused function fix.]
> [applied Uladzislau feedback on locking.]
> Link: https://lkml.kernel.org/r/20230904180806.1002832-1-joel@joelfernandes.org
> Fixes: 98f180837a89 ("mm: Make mem_dump_obj() handle vmalloc() memory")
> Signed-off-by: Joel Fernandes (Google) <joel@joelfernandes.org>
> Reviewed-by: Uladzislau Rezki (Sony) <urezki@gmail.com>
> Reported-by: Zhen Lei <thunder.leizhen@huaweicloud.com>
> Cc: Paul E. McKenney <paulmck@kernel.org>
> Cc: Zqiang <qiang.zhang1211@gmail.com>
> Cc: <stable@vger.kernel.org>
> Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
> ---
>
> mm/vmalloc.c | 26 ++++++++++++++++++++++----
> 1 file changed, 22 insertions(+), 4 deletions(-)
>
> --- a/mm/vmalloc.c~mm-vmalloc-add-a-safer-version-of-find_vm_area-for-debug
> +++ a/mm/vmalloc.c
> @@ -4278,14 +4278,32 @@ void pcpu_free_vm_areas(struct vm_struct
> #ifdef CONFIG_PRINTK
> bool vmalloc_dump_obj(void *object)
> {
> - struct vm_struct *vm;
> void *objp = (void *)PAGE_ALIGN((unsigned long)object);
> + const void *caller;
> + struct vm_struct *vm;
> + struct vmap_area *va;
> + unsigned long addr;
> + unsigned int nr_pages;
> +
> + if (!spin_trylock(&vmap_area_lock))
> + return false;
> + va = __find_vmap_area((unsigned long)objp, &vmap_area_root);
> + if (!va) {
> + spin_unlock(&vmap_area_lock);
> + return false;
> + }
>
> - vm = find_vm_area(objp);
> - if (!vm)
> + vm = va->vm;
> + if (!vm) {
> + spin_unlock(&vmap_area_lock);
> return false;
> + }
> + addr = (unsigned long)vm->addr;
> + caller = vm->caller;
> + nr_pages = vm->nr_pages;
> + spin_unlock(&vmap_area_lock);
> pr_cont(" %u-page vmalloc region starting at %#lx allocated at %pS\n",
> - vm->nr_pages, (unsigned long)vm->addr, vm->caller);
> + nr_pages, addr, caller);
> return true;
> }
> #endif
> _
>
> Patches currently in -mm which might be from joel@joelfernandes.org are
>
>


--
Lorenzo Stoakes
https://ljs.io

\
 
 \ /
  Last update: 2023-09-06 21:48    [W:0.042 / U:0.736 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site