From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-16.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 9776DC07E95 for ; Wed, 14 Jul 2021 02:35:09 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 823D86135A for ; Wed, 14 Jul 2021 02:35:09 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237375AbhGNCh7 (ORCPT ); Tue, 13 Jul 2021 22:37:59 -0400 Received: from mail108.syd.optusnet.com.au ([211.29.132.59]:34427 "EHLO mail108.syd.optusnet.com.au" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237457AbhGNCh7 (ORCPT ); Tue, 13 Jul 2021 22:37:59 -0400 Received: from dread.disaster.area (pa49-181-34-10.pa.nsw.optusnet.com.au [49.181.34.10]) by mail108.syd.optusnet.com.au (Postfix) with ESMTPS id E01D81B1176; Wed, 14 Jul 2021 12:34:47 +1000 (AEST) Received: from discord.disaster.area ([192.168.253.110]) by dread.disaster.area with esmtp (Exim 4.92.3) (envelope-from ) id 1m3UjW-006Hef-Qa; Wed, 14 Jul 2021 12:34:46 +1000 Received: from dave by discord.disaster.area with local (Exim 4.94) (envelope-from ) id 1m3UjW-00Awej-Ih; Wed, 14 Jul 2021 12:34:46 +1000 From: Dave Chinner To: linux-xfs@vger.kernel.org Cc: linux-mm@kvack.org Subject: [PATCH 1/3] mm: Add kvrealloc() Date: Wed, 14 Jul 2021 12:34:38 +1000 Message-Id: <20210714023440.2608690-2-david@fromorbit.com> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20210714023440.2608690-1-david@fromorbit.com> References: <20210714023440.2608690-1-david@fromorbit.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Optus-CM-Score: 0 X-Optus-CM-Analysis: v=2.3 cv=F8MpiZpN c=1 sm=1 tr=0 a=hdaoRb6WoHYrV466vVKEyw==:117 a=hdaoRb6WoHYrV466vVKEyw==:17 a=e_q4qTt1xDgA:10 a=20KFwNOVAAAA:8 a=FgU_YNmxFDRv79IIi3MA:9 Precedence: bulk List-ID: X-Mailing-List: linux-xfs@vger.kernel.org From: Dave Chinner During log recovery of an XFS filesystem with 64kB directory buffers, rebuilding a buffer split across two log records results in a memory allocation warning from krealloc like this: xfs filesystem being mounted at /mnt/scratch supports timestamps until 2038 (0x7fffffff) XFS (dm-0): Unmounting Filesystem XFS (dm-0): Mounting V5 Filesystem XFS (dm-0): Starting recovery (logdev: internal) ------------[ cut here ]------------ WARNING: CPU: 5 PID: 3435170 at mm/page_alloc.c:3539 get_page_from_freelist+0xdee/0xe40 ..... RIP: 0010:get_page_from_freelist+0xdee/0xe40 Call Trace: ? complete+0x3f/0x50 __alloc_pages+0x16f/0x300 alloc_pages+0x87/0x110 kmalloc_order+0x2c/0x90 kmalloc_order_trace+0x1d/0x90 __kmalloc_track_caller+0x215/0x270 ? xlog_recover_add_to_cont_trans+0x63/0x1f0 krealloc+0x54/0xb0 xlog_recover_add_to_cont_trans+0x63/0x1f0 xlog_recovery_process_trans+0xc1/0xd0 xlog_recover_process_ophdr+0x86/0x130 xlog_recover_process_data+0x9f/0x160 xlog_recover_process+0xa2/0x120 xlog_do_recovery_pass+0x40b/0x7d0 ? __irq_work_queue_local+0x4f/0x60 ? irq_work_queue+0x3a/0x50 xlog_do_log_recovery+0x70/0x150 xlog_do_recover+0x38/0x1d0 xlog_recover+0xd8/0x170 xfs_log_mount+0x181/0x300 xfs_mountfs+0x4a1/0x9b0 xfs_fs_fill_super+0x3c0/0x7b0 get_tree_bdev+0x171/0x270 ? suffix_kstrtoint.constprop.0+0xf0/0xf0 xfs_fs_get_tree+0x15/0x20 vfs_get_tree+0x24/0xc0 path_mount+0x2f5/0xaf0 __x64_sys_mount+0x108/0x140 do_syscall_64+0x3a/0x70 entry_SYSCALL_64_after_hwframe+0x44/0xae Essentially, we are taking a multi-order allocation from kmem_alloc() (which has an open coded no fail, no warn loop) and then reallocating it out to 64kB using krealloc(__GFP_NOFAIL) and that is then triggering the above warning. This is a regression caused by converting this code from an open coded no fail/no warn reallocation loop to using __GFP_NOFAIL. What we actually need here is kvrealloc(), so that if contiguous page allocation fails we fall back to vmalloc() and we don't get nasty warnings happening in XFS. Fixes: 771915c4f688 ("xfs: remove kmem_realloc()") Signed-off-by: Dave Chinner --- fs/xfs/xfs_log_recover.c | 4 +++- include/linux/mm.h | 2 ++ mm/util.c | 15 +++++++++++++++ 3 files changed, 20 insertions(+), 1 deletion(-) diff --git a/fs/xfs/xfs_log_recover.c b/fs/xfs/xfs_log_recover.c index 1721fce2ec94..3c08d495844d 100644 --- a/fs/xfs/xfs_log_recover.c +++ b/fs/xfs/xfs_log_recover.c @@ -2062,7 +2062,9 @@ xlog_recover_add_to_cont_trans( old_ptr = item->ri_buf[item->ri_cnt-1].i_addr; old_len = item->ri_buf[item->ri_cnt-1].i_len; - ptr = krealloc(old_ptr, len + old_len, GFP_KERNEL | __GFP_NOFAIL); + ptr = kvrealloc(old_ptr, old_len, len + old_len, GFP_KERNEL); + if (!ptr) + return -ENOMEM; memcpy(&ptr[old_len], dp, len); item->ri_buf[item->ri_cnt-1].i_len += len; item->ri_buf[item->ri_cnt-1].i_addr = ptr; diff --git a/include/linux/mm.h b/include/linux/mm.h index 57453dba41b9..ff9c00bfb76d 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -829,6 +829,8 @@ static inline void *kvcalloc(size_t n, size_t size, gfp_t flags) return kvmalloc_array(n, size, flags | __GFP_ZERO); } +extern void *kvrealloc(const void *p, size_t oldsize, size_t newsize, + gfp_t flags); extern void kvfree(const void *addr); extern void kvfree_sensitive(const void *addr, size_t len); diff --git a/mm/util.c b/mm/util.c index 99c6cc77de9e..b7698d6b2226 100644 --- a/mm/util.c +++ b/mm/util.c @@ -635,6 +635,21 @@ void kvfree_sensitive(const void *addr, size_t len) } EXPORT_SYMBOL(kvfree_sensitive); +void *kvrealloc(const void *p, size_t oldsize, size_t newsize, gfp_t flags) +{ + void *newp; + + if (oldsize >= newsize) + return (void *)p; + newp = kvmalloc(newsize, flags); + if (!newp) + return NULL; + memcpy(newp, p, oldsize); + kvfree(p); + return newp; +} +EXPORT_SYMBOL(kvrealloc); + static inline void *__page_rmapping(struct page *page) { unsigned long mapping; -- 2.31.1