From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 05F685F869 for ; Wed, 17 Apr 2024 21:16:38 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1713388599; cv=none; b=utueOv6gWXcQvQENZbhieVUCOGtETIo8HUZJlv0KeHSyjTy5WHliKgxRzj+96R48ciHg2YHkggKp/y9eLAspMuSYFZfK8Hr3aK3Dqf2i0QJrUJzbr7ZCn4ErtXyQa65+jV+PbJ95IZXIrKOp86g2Y9ADmkpB9E9r6PcNSW6/wPs= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1713388599; c=relaxed/simple; bh=S/dk8lSRR7lGgrVclOK0C3kAO6H6YGGnc0M0eNWpgBg=; h=Date:To:From:Subject:Message-Id; b=R0N+lIwkKMSQU7yfvsqbpr78Ft/1olgPMgVQU96v1xSHzR9gYj2iAYxWlfAy/K160Ieuz5tcD629+k2+wqanhoodAaxLfDMujBfmBRvI3stqLjt9m8tp47usoDNBUeK6GKiCPr8v4/D2frtUMwPjSNaUQvR3LuXmltxpcu2fWhc= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b=I6Gz+KZZ; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b="I6Gz+KZZ" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 784F7C072AA; Wed, 17 Apr 2024 21:16:38 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1713388598; bh=S/dk8lSRR7lGgrVclOK0C3kAO6H6YGGnc0M0eNWpgBg=; h=Date:To:From:Subject:From; b=I6Gz+KZZL9/rIOlDtcllW9fEpWK/y8gaa/V1lfZkrkZBF50Cycc0qBjRdvlXSp9VT 47XqPjUnjJJgvLR5w2HvMZC1uT28h5GRMzi/vLLpWQRa0/tM7xKseQ9cd2UVDCjGIZ V/87YF/ghGy9P1NxoaBaMEUtESyZaQeSWEXX/D10= Date: Wed, 17 Apr 2024 14:16:37 -0700 To: mm-commits@vger.kernel.org,yosryahmed@google.com,vitaly.wool@konsulko.com,sjenning@redhat.com,rjones@redhat.com,nphamcs@gmail.com,ddstreet@ieee.org,christian@heusel.eu,chengming.zhou@linux.dev,hannes@cmpxchg.org,akpm@linux-foundation.org From: Andrew Morton Subject: + null-pointer-dereference-while-shrinking-zswap.patch added to mm-hotfixes-unstable branch Message-Id: <20240417211638.784F7C072AA@smtp.kernel.org> Precedence: bulk X-Mailing-List: mm-commits@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: The patch titled Subject: Re: Null pointer dereference while shrinking zswap has been added to the -mm mm-hotfixes-unstable branch. Its filename is null-pointer-dereference-while-shrinking-zswap.patch This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/null-pointer-dereference-while-shrinking-zswap.patch This patch will later appear in the mm-hotfixes-unstable branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/process/submit-checklist.rst when testing your code *** The -mm tree is included into linux-next via the mm-everything branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm and is updated there every 2-3 working days ------------------------------------------------------ From: Johannes Weiner Subject: Re: Null pointer dereference while shrinking zswap Date: Wed, 17 Apr 2024 10:33:24 -0400 temp version of this fix, for testing Link: https://lkml.kernel.org/r/20240417143324.GA1055428@cmpxchg.org Signed-off-by: Johannes Weiner Tested-by: Richard W.M. Jones Tested-By: Christian Heusel Cc: Chengming Zhou Cc: Dan Streetman Cc: Nhat Pham Cc: Seth Jennings Cc: Vitaly Wool Cc: Yosry Ahmed Signed-off-by: Andrew Morton --- mm/zswap.c | 25 ++++++++++++++++--------- 1 file changed, 16 insertions(+), 9 deletions(-) --- a/mm/zswap.c~null-pointer-dereference-while-shrinking-zswap +++ a/mm/zswap.c @@ -1331,15 +1331,22 @@ static unsigned long zswap_shrinker_coun if (!gfp_has_io_fs(sc->gfp_mask)) return 0; -#ifdef CONFIG_MEMCG_KMEM - mem_cgroup_flush_stats(memcg); - nr_backing = memcg_page_state(memcg, MEMCG_ZSWAP_B) >> PAGE_SHIFT; - nr_stored = memcg_page_state(memcg, MEMCG_ZSWAPPED); -#else - /* use pool stats instead of memcg stats */ - nr_backing = zswap_pool_total_size >> PAGE_SHIFT; - nr_stored = atomic_read(&zswap_nr_stored); -#endif + /* + * For memcg, use the cgroup-wide ZSWAP stats since we don't + * have them per-node and thus per-lruvec. Careful if memcg is + * runtime-disabled: we can get sc->memcg == NULL, which is ok + * for the lruvec, but not for memcg_page_state(). + * + * Without memcg, use the zswap pool-wide metrics. + */ + if (!mem_cgroup_disabled()) { + mem_cgroup_flush_stats(memcg); + nr_backing = memcg_page_state(memcg, MEMCG_ZSWAP_B) >> PAGE_SHIFT; + nr_stored = memcg_page_state(memcg, MEMCG_ZSWAPPED); + } else { + nr_backing = zswap_pool_total_size >> PAGE_SHIFT; + nr_stored = atomic_read(&zswap_nr_stored); + } if (!nr_stored) return 0; _ Patches currently in -mm which might be from hannes@cmpxchg.org are null-pointer-dereference-while-shrinking-zswap.patch mm-zswap-optimize-zswap-pool-size-tracking.patch mm-zpool-return-pool-size-in-pages.patch mm-page_alloc-remove-pcppage-migratetype-caching.patch mm-page_alloc-optimize-free_unref_folios.patch mm-page_alloc-fix-up-block-types-when-merging-compatible-blocks.patch mm-page_alloc-move-free-pages-when-converting-block-during-isolation.patch mm-page_alloc-fix-move_freepages_block-range-error.patch mm-page_alloc-fix-freelist-movement-during-block-conversion.patch mm-page_alloc-close-migratetype-race-between-freeing-and-stealing.patch mm-page_isolation-prepare-for-hygienic-freelists.patch mm-page_isolation-prepare-for-hygienic-freelists-fix.patch mm-page_alloc-consolidate-free-page-accounting.patch mm-page_alloc-consolidate-free-page-accounting-fix.patch mm-page_alloc-consolidate-free-page-accounting-fix-2.patch mm-page_alloc-batch-vmstat-updates-in-expand.patch