On 30.09.2020 15:50, Alexander Potapenko wrote: > On Tue, Sep 29, 2020 at 8:35 PM Alexander Popov <alex.popov@xxxxxxxxx> wrote: >> >> Currently in CONFIG_SLAB init_on_free happens too late, and heap >> objects go to the heap quarantine being dirty. Lets move memory >> clearing before calling kasan_slab_free() to fix that. >> >> Signed-off-by: Alexander Popov <alex.popov@xxxxxxxxx> > Reviewed-by: Alexander Potapenko <glider@xxxxxxxxxx> Hello! Can this particular patch be considered for the mainline kernel? Note: I summarized the results of the experiment with the Linux kernel heap quarantine in a short article, for future reference: https://a13xp0p0v.github.io/2020/11/30/slab-quarantine.html Best regards, Alexander >> --- >> mm/slab.c | 5 +++-- >> 1 file changed, 3 insertions(+), 2 deletions(-) >> >> diff --git a/mm/slab.c b/mm/slab.c >> index 3160dff6fd76..5140203c5b76 100644 >> --- a/mm/slab.c >> +++ b/mm/slab.c >> @@ -3414,6 +3414,9 @@ static void cache_flusharray(struct kmem_cache *cachep, struct array_cache *ac) >> static __always_inline void __cache_free(struct kmem_cache *cachep, void *objp, >> unsigned long caller) >> { >> + if (unlikely(slab_want_init_on_free(cachep))) >> + memset(objp, 0, cachep->object_size); >> + >> /* Put the object into the quarantine, don't touch it for now. */ >> if (kasan_slab_free(cachep, objp, _RET_IP_)) >> return; >> @@ -3432,8 +3435,6 @@ void ___cache_free(struct kmem_cache *cachep, void *objp, >> struct array_cache *ac = cpu_cache_get(cachep); >> >> check_irq_off(); >> - if (unlikely(slab_want_init_on_free(cachep))) >> - memset(objp, 0, cachep->object_size); >> kmemleak_free_recursive(objp, cachep->flags); >> objp = cache_free_debugcheck(cachep, objp, caller); >> memcg_slab_free_hook(cachep, virt_to_head_page(objp), objp); >> -- >> 2.26.2 >> > >
