The patch titled
Subject: mm/vmalloc: add a safer version of find_vm_area() for debug
has been added to the -mm mm-hotfixes-unstable branch. Its filename is
mm-vmalloc-add-a-safer-version-of-find_vm_area-for-debug.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-vmalloc-add-a-safer-version-of-find_vm_area-for-debug.patch
This patch will later appear in the mm-hotfixes-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: "Joel Fernandes (Google)" <joel@xxxxxxxxxxxxxxxxx>
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@xxxxxxxxxxxxxxxxx
Fixes: 98f180837a89 ("mm: Make mem_dump_obj() handle vmalloc() memory")
Signed-off-by: Joel Fernandes (Google) <joel@xxxxxxxxxxxxxxxxx>
Reviewed-by: Uladzislau Rezki (Sony) <urezki@xxxxxxxxx>
Reported-by: Zhen Lei <thunder.leizhen@xxxxxxxxxxxxxxx>
Cc: Paul E. McKenney <paulmck@xxxxxxxxxx>
Cc: Zqiang <qiang.zhang1211@xxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx>
Cc: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
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@xxxxxxxxxxxxxxxxx are
mm-vmalloc-add-a-safer-version-of-find_vm_area-for-debug.patch
