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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 9A773C433EF for ; Fri, 22 Apr 2022 12:05:18 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1447281AbiDVMIJ (ORCPT ); Fri, 22 Apr 2022 08:08:09 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60774 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1447349AbiDVMHk (ORCPT ); Fri, 22 Apr 2022 08:07:40 -0400 Received: from mail-ed1-x52e.google.com (mail-ed1-x52e.google.com [IPv6:2a00:1450:4864:20::52e]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id CC4C556C14 for ; Fri, 22 Apr 2022 05:03:57 -0700 (PDT) Received: by mail-ed1-x52e.google.com with SMTP id 21so10167667edv.1 for ; Fri, 22 Apr 2022 05:03:57 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=L93WxvqHz29c/rmoHema7YmVwi6Brmln6rC6CF3ndfw=; b=QkLtGIFV16f1/E7XJzRlvDDanUYCSfXAV74OblwBQqqxCHRVboIzsmFIQ1dRB7EqwT mn6y3e6Y/FwtdEMiZmvL6kTKGvMtvymztwFmuB2WKgWWRGBhan8I3IF4LXlXgdvG6bL7 fafi8FLR6w28r1t2h7NYVkImYTeE3JPyRnBaMtifn4zoESMbhSXijhM9DnrXHBfTKAmW KX7g0eEtyMfdNaU0zBgAde+BSACpcLqSMvTyawgO53N6iC0ZhGr70xa08blhQe/TTPeq 2TZy36NECfqpW1rp48ci1G8aTkqNGcvNUA68fCODd684w3tDUlBNna49YdzM2yHscxdJ H33g== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=L93WxvqHz29c/rmoHema7YmVwi6Brmln6rC6CF3ndfw=; b=QKUsc9fRlfngZQKJcUKlVJChNk++Z2YPq3VIAmNfBYEwcIL8V9DSY8FX3Fw9xIEIIK Qe0ZRFd1OcAihLDyLTtZeU5bqHQ3R7zToIOdxWGApxr2uFxh8N/2NxdH+XxmOG7yp+uK fzceEn6xSHOE/CBS4K8b8MgcFP6tjxqhgL1vCtMFyxm4IGExGciKLvMSBDxb77dqpj2S yhY8bTAcgAm+9r6fCiU26dl4ZgI+P/aSjCjSaYjfRPEMdrkJU/hoeCiN5egs06SMrxpN +sU2St+aNYn6j44H3+4BAHGocnzavMn8Hg3PVYHthGoojdFou8/P7tHkr2+JmDsUmbDU +oYw== X-Gm-Message-State: AOAM532xNTT1tcS5Xl8iCZ8lbz5oOf6ImFPUwDI01x6NMIpkDHKrdN1b AgkQYIXtuk2NjgHpCnAbAjYTxsWuBok= X-Google-Smtp-Source: ABdhPJyDZxRVtH3OzjzkNjiyJdfGFInQpz+DI3yNmkSVbo8oBGVtgwHMR8MjKS1f0Q29fUVtQ3DmjA== X-Received: by 2002:a50:eb89:0:b0:425:c2de:7c01 with SMTP id y9-20020a50eb89000000b00425c2de7c01mr1338584edr.282.1650629036340; Fri, 22 Apr 2022 05:03:56 -0700 (PDT) Received: from localhost.localdomain ([5.29.13.154]) by smtp.gmail.com with ESMTPSA id x24-20020a1709064bd800b006ef606fe5c1sm697026ejv.43.2022.04.22.05.03.55 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 22 Apr 2022 05:03:55 -0700 (PDT) From: Amir Goldstein To: Jan Kara Cc: Matthew Bobrowski , linux-fsdevel@vger.kernel.org Subject: [PATCH v4 15/16] fanotify: use fsnotify group lock helpers Date: Fri, 22 Apr 2022 15:03:26 +0300 Message-Id: <20220422120327.3459282-16-amir73il@gmail.com> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20220422120327.3459282-1-amir73il@gmail.com> References: <20220422120327.3459282-1-amir73il@gmail.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org Direct reclaim from fanotify mark allocation context may try to evict inodes with evictable marks of the same group and hit this deadlock: [<0>] fsnotify_destroy_mark+0x1f/0x3a [<0>] fsnotify_destroy_marks+0x71/0xd9 [<0>] __destroy_inode+0x24/0x7e [<0>] destroy_inode+0x2c/0x67 [<0>] dispose_list+0x49/0x68 [<0>] prune_icache_sb+0x5b/0x79 [<0>] super_cache_scan+0x11c/0x16f [<0>] shrink_slab.constprop.0+0x23e/0x40f [<0>] shrink_node+0x218/0x3e7 [<0>] do_try_to_free_pages+0x12a/0x2d2 [<0>] try_to_free_pages+0x166/0x242 [<0>] __alloc_pages_slowpath.constprop.0+0x30c/0x903 [<0>] __alloc_pages+0xeb/0x1c7 [<0>] cache_grow_begin+0x6f/0x31e [<0>] fallback_alloc+0xe0/0x12d [<0>] ____cache_alloc_node+0x15a/0x17e [<0>] kmem_cache_alloc_trace+0xa1/0x143 [<0>] fanotify_add_mark+0xd5/0x2b2 [<0>] do_fanotify_mark+0x566/0x5eb [<0>] __x64_sys_fanotify_mark+0x21/0x24 [<0>] do_syscall_64+0x6d/0x80 [<0>] entry_SYSCALL_64_after_hwframe+0x44/0xae Set the FSNOTIFY_GROUP_NOFS flag to prevent going into direct reclaim from allocations under fanotify group lock and use the safe group lock helpers. Suggested-by: Jan Kara Link: https://lore.kernel.org/r/20220321112310.vpr7oxro2xkz5llh@quack3.lan/ Signed-off-by: Amir Goldstein --- fs/notify/fanotify/fanotify_user.c | 14 +++++++------- 1 file changed, 7 insertions(+), 7 deletions(-) diff --git a/fs/notify/fanotify/fanotify_user.c b/fs/notify/fanotify/fanotify_user.c index ae36138afead..228cf25e9230 100644 --- a/fs/notify/fanotify/fanotify_user.c +++ b/fs/notify/fanotify/fanotify_user.c @@ -1035,10 +1035,10 @@ static int fanotify_remove_mark(struct fsnotify_group *group, __u32 removed; int destroy_mark; - mutex_lock(&group->mark_mutex); + fsnotify_group_lock(group); fsn_mark = fsnotify_find_mark(connp, group); if (!fsn_mark) { - mutex_unlock(&group->mark_mutex); + fsnotify_group_unlock(group); return -ENOENT; } @@ -1048,7 +1048,7 @@ static int fanotify_remove_mark(struct fsnotify_group *group, fsnotify_recalc_mask(fsn_mark->connector); if (destroy_mark) fsnotify_detach_mark(fsn_mark); - mutex_unlock(&group->mark_mutex); + fsnotify_group_unlock(group); if (destroy_mark) fsnotify_free_mark(fsn_mark); @@ -1196,13 +1196,13 @@ static int fanotify_add_mark(struct fsnotify_group *group, bool recalc; int ret = 0; - mutex_lock(&group->mark_mutex); + fsnotify_group_lock(group); fsn_mark = fsnotify_find_mark(connp, group); if (!fsn_mark) { fsn_mark = fanotify_add_new_mark(group, connp, obj_type, fan_flags, fsid); if (IS_ERR(fsn_mark)) { - mutex_unlock(&group->mark_mutex); + fsnotify_group_unlock(group); return PTR_ERR(fsn_mark); } } @@ -1231,7 +1231,7 @@ static int fanotify_add_mark(struct fsnotify_group *group, fsnotify_recalc_mask(fsn_mark->connector); out: - mutex_unlock(&group->mark_mutex); + fsnotify_group_unlock(group); fsnotify_put_mark(fsn_mark); return ret; @@ -1385,7 +1385,7 @@ SYSCALL_DEFINE2(fanotify_init, unsigned int, flags, unsigned int, event_f_flags) /* fsnotify_alloc_group takes a ref. Dropped in fanotify_release */ group = fsnotify_alloc_group(&fanotify_fsnotify_ops, - FSNOTIFY_GROUP_USER); + FSNOTIFY_GROUP_USER | FSNOTIFY_GROUP_NOFS); if (IS_ERR(group)) { return PTR_ERR(group); } -- 2.35.1