> On Sep 6, 2023, at 3:14 PM, Lorenzo Stoakes <lstoakes@xxxxxxxxx> wrote: > > On Wed, 6 Sept 2023 at 16:09, Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> 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... That works me because we also had some disagreements on some of the suggestions! Looking forward to your patch and discussing it! Cheers, - Joel > > >> >> ------------------------------------------------------ >> 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 >> >> > > > -- > Lorenzo Stoakes > https://ljs.io
