From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pl1-f172.google.com (mail-pl1-f172.google.com [209.85.214.172]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id A30F42571D7 for ; Sun, 5 Jul 2026 04:24:05 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.214.172 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1783225447; cv=none; b=dpayT6L33U2ZWOGqOTOBa1Ods8FL3RsJtb2S5N+sAl50hegRCebvZx4jA9Cmi2aQN4ZjVs5p75FlbEikd3dLscW2+kV1LBexDYLSMiYdN8Wh3StYBEQGWh5prxwXpVMXrF8l6luuCLa/jeWExNbHlc5xrXsDU1R87Ed1GUH+RxQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1783225447; c=relaxed/simple; bh=gaWEmoAqGz2gI8UM4wvQIMUiYnddD6uwYAV7tsNQyUA=; h=From:To:Cc:Subject:Date:Message-Id:MIME-Version; b=rmnkaugA+POPzRd6EDZz/Ff8OhwwwjFULQDh6b6jVnHpBUgCK5yBtEwu2TYrlvPEtFVN80ze616nfPdvIcTqczPBz8vSFsskKcAX0ALbbTryxDDMyvFKptC4j6EXJT9oKufoZjhkmjXnVZ/F71UzVQ83m4ujLNzvYccTgC6qmb0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=XK2l9/hD; arc=none smtp.client-ip=209.85.214.172 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="XK2l9/hD" Received: by mail-pl1-f172.google.com with SMTP id d9443c01a7336-2c9b1edf2bdso19373915ad.1 for ; Sat, 04 Jul 2026 21:24:05 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20251104; t=1783225445; x=1783830245; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:from:to:cc:subject:date:message-id:reply-to; bh=Zdkx5BeLCr6nbuoTGiyaraoBUMYitX0MiD9jquX48zc=; b=XK2l9/hDtTVXXTFzqS8rRtL6BmDWl6fV0VuK5+FUjmIDWjHBoRXqMdmTvXiAC0VtLF cm8SYJzvZUMEQcXEJzJhvQyb9b0ur+u/+ktWNO9kCnq9mPZJjKzr+rJCzjN4DoPVBzaQ +OL85A70tWt90cSZo+CFmvfpx9AeCcIBlUKxEUz+pI7FOEt20BE08GcnQ/h3HwoV7+BO 8xMcGUV54CN19cNAFSLk6n4Weam+mQgu7COSwkYcMaGudio5qGUjaSbqHN/r/AY/2EAB f85Is4rIpcv8TX5f5vleOwkkmikh7CUppsz9E9BNbBVK41gpm7AvtHF1fPhY1ALN4V6V eu8g== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1783225445; x=1783830245; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:x-gm-gg:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=Zdkx5BeLCr6nbuoTGiyaraoBUMYitX0MiD9jquX48zc=; b=AE4w/mCq/SMHNu3LJGHZwsU35M68lBXKNv3wzcXwyr+D2ubwiZ+QAAFOd+330s8mHj b5nUTinZEuFI0c9w+kmR+akmtIg7Ezc6kZ+C4M5jo+6CSk/lz2+Lk/8Lnpqc8SDQidU7 VEoS+Ul6jBvq/bsdUIC9O1o+7Mh47UlgVHJJ3WXBrMjrt/mwfdL87fP35TFfMPMksrs7 kCKRvEmZhM8cNCsk9vWiA0xbzccrCbIFdqp/1dd6zn5N0gZzZnwkkYqi9DbQX2A+y1lq +YEEbbZ11qJdI3CX4OvZgbvLTG0YCczpIQ4tttO2M452LU16SzanY54f3AAZxDLLVQmV TzVQ== X-Forwarded-Encrypted: i=1; AHgh+Rq31yFdAueayU9CJ2cDsg595tRHThuSq5WYLHJ0tAc3qKogEJJqKAyGk3y3vOXBiyGgfpoutd1qvifIWtg=@vger.kernel.org X-Gm-Message-State: AOJu0YyHoyvUMCEv7sOTTJnVLnHWjCdoswLoRa5jGVh7Ioh3wGU4gOuh hSNazx6wsBiyRS1ll1POPbfxY0CFshkCNwhfJXAs+8X+Et7Edv6j8otO X-Gm-Gg: AfdE7cmtwBVaLVnMu5jZNpaU+Wv6rmAQdG+TRp8UjMgTa1J98ElfwI5DkFsvxsNbqlT iM/ogf9DQ6n/Qz/bUwic4QmVeUr0//Ns64gHFCgAgm6cNhMGYxwjJ7dwgZJ0Z9Qe/AXIueT656/ sxXW1PsNE1/addNvVNpbH5UZghGwvILeJADCzNeXBtwklfy1OlgvpBVXVbKuA4EvpsmI9ACEOnq WLVegkQKjTksGoxIoteXtxvlwYcujr4e480mRl1dD9YmBUyXQyUCq8H0olLb015LZEyPu9QDTQx ugq7iSzAhENBGwhOoOEuIv+uSITQB4UxMJF5C8J0cpLTxgAEB/ytIRtmarYr4bHBlLgywWCiFRX 4bNSFaRFUA0LEE3k5VLPLsoonUXUaOFO4g8ahVCvF1hdvIxrNZ2NXbwQgUQhjygANP9y8fNCMV5 dOy0OyocycGg4ASV1hEA== X-Received: by 2002:a17:902:d585:b0:2ca:b1f6:b0c5 with SMTP id d9443c01a7336-2cbb9f0665emr51255765ad.38.1783225444840; Sat, 04 Jul 2026 21:24:04 -0700 (PDT) Received: from localhost ([111.228.63.84]) by smtp.gmail.com with ESMTPSA id d9443c01a7336-2cad789424esm29519575ad.76.2026.07.04.21.24.01 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sat, 04 Jul 2026 21:24:04 -0700 (PDT) From: Cen Zhang To: Carlos Maiolino , Damien Le Moal , Hans Holmberg Cc: linux-xfs@vger.kernel.org, linux-kernel@vger.kernel.org, baijiaju1990@gmail.com, zzzccc427@gmail.com Subject: [PATCH v3] xfs: tie zoned sysfs lifetime to zone info Date: Sun, 5 Jul 2026 12:23:58 +0800 Message-Id: <20260705042358.3667466-1-zzzccc427@gmail.com> X-Mailer: git-send-email 2.34.1 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit The zoned sysfs directory is currently registered as part of the generic per-mount sysfs setup, but the data exposed by nr_open_zones has a narrower lifetime. mp->m_zone_info is allocated by xfs_mount_zones() and freed by xfs_unmount_zones(), while the zoned sysfs kobject remained registered until xfs_mount_sysfs_del(). A read of nr_open_zones can therefore enter through the still-live sysfs kobject after xfs_unmount_zones() has freed mp->m_zone_info, leading to a use-after-free in nr_open_zones_show(). Make the zoned sysfs lifetime match the zone-info lifetime inside the zone allocator. Create the zoned sysfs directory from xfs_mount_zones() after the zone allocator has finished setting up, and remove it as the first step of xfs_unmount_zones(), before any zone allocator teardown can free m_zone_info. Sysfs removal deactivates the kernfs nodes and waits for active callbacks to drain before returning, so this also protects a reader that has already entered nr_open_zones_show() but has not yet dereferenced m_zone_info. Validation reproduced this kernel report: BUG: KASAN: slab-use-after-free in nr_open_zones_show+0x86/0x90 The buggy address belongs to the object at ffff88810b177800 which belongs to the cache kmalloc-1k of size 1024 The buggy address is located 160 bytes inside of freed 1024-byte region [ffff88810b177800, ffff88810b177c00) Read of size 4 Call trace: print_report+0xcd/0x620 nr_open_zones_show+0x86/0x90 (fs/xfs/xfs_sysfs.c:724) srso_alias_return_thunk+0x5/0xfbef5 __virt_addr_valid+0x20c/0x410 kasan_report+0xdd/0x110 sysfs_kf_seq_show+0x1bd/0x380 seq_read_iter+0x40f/0x11b0 lock_release+0xba/0x260 mark_held_locks+0x40/0x70 vfs_read+0x717/0xce0 __up_read+0x319/0x900 ksys_read+0xf8/0x1c0 do_user_addr_fault+0x3d0/0xbc0 trace_hardirqs_on_prepare+0x23/0xf0 do_syscall_64+0xc8/0x530 (arch/x86/entry/syscall_64.c:87) entry_SYSCALL_64_after_hwframe+0x74/0x7c Allocated by task stack: kasan_save_stack+0x33/0x60 kasan_save_track+0x14/0x30 __kasan_kmalloc+0xaa/0xb0 __kmalloc_cache_noprof+0x205/0x460 xfs_mount_zones+0x34c/0x2650 xfs_mountfs+0x1b97/0x1eb0 xfs_fs_fill_super+0xf2b/0x18a0 get_tree_bdev_flags+0x310/0x590 vfs_get_tree+0x8d/0x2e0 __x64_sys_fsconfig+0x61c/0xbc0 do_syscall_64+0xc8/0x530 (arch/x86/entry/syscall_64.c:87) entry_SYSCALL_64_after_hwframe+0x74/0x7c Freed by task stack: kasan_save_stack+0x33/0x60 kasan_save_track+0x14/0x30 kasan_save_free_info+0x3b/0x60 __kasan_slab_free+0x5f/0x80 kfree+0x20e/0x4c0 xfs_unmountfs+0x2fd/0x390 xfs_fs_put_super+0x60/0x110 generic_shutdown_super+0x143/0x4b0 kill_block_super+0x3b/0x90 xfs_kill_sb+0x12/0x50 deactivate_locked_super+0xa7/0x160 cleanup_mnt+0x218/0x420 task_work_run+0x11a/0x1f0 exit_to_user_mode_loop+0x13c/0x4f0 do_syscall_64+0x4a9/0x530 (arch/x86/entry/syscall_64.c:87) entry_SYSCALL_64_after_hwframe+0x74/0x7c Fixes: 62c89988dc19 ("xfs: expose the number of open zones in sysfs") Assisted-by: Codex:gpt-5.5 Signed-off-by: Cen Zhang --- v3: Move zoned sysfs setup and teardown into xfs_mount_zones() and xfs_unmount_zones() so the zone allocator owns the sysfs files that expose m_zone_info. Unwind zone GC before freeing m_zone_info if zoned sysfs setup fails. Document that sysfs removal drains active show/store callbacks before m_zone_info is freed. v2: Tear down the zoned sysfs directory before freeing m_zone_info instead of serializing nr_open_zones_show() with s_umount. fs/xfs/xfs_sysfs.c | 28 +++++++++++++++++----------- fs/xfs/xfs_sysfs.h | 2 ++ fs/xfs/xfs_zone_alloc.c | 8 ++++++++ 3 files changed, 27 insertions(+), 11 deletions(-) diff --git a/fs/xfs/xfs_sysfs.c b/fs/xfs/xfs_sysfs.c index 676777064c2d..b62712187324 100644 --- a/fs/xfs/xfs_sysfs.c +++ b/fs/xfs/xfs_sysfs.c @@ -780,6 +780,23 @@ static const struct kobj_type xfs_zoned_ktype = { .default_groups = xfs_zoned_groups, }; +int +xfs_zoned_sysfs_init(struct xfs_mount *mp) +{ + if (!IS_ENABLED(CONFIG_XFS_RT) || !xfs_has_zoned(mp)) + return 0; + + return xfs_sysfs_init(&mp->m_zoned_kobj, &xfs_zoned_ktype, + &mp->m_kobj, "zoned"); +} + +void +xfs_zoned_sysfs_del(struct xfs_mount *mp) +{ + if (IS_ENABLED(CONFIG_XFS_RT) && xfs_has_zoned(mp)) + xfs_sysfs_del(&mp->m_zoned_kobj); +} + int xfs_mount_sysfs_init( struct xfs_mount *mp) @@ -820,14 +837,6 @@ xfs_mount_sysfs_init( if (error) goto out_remove_error_dir; - if (IS_ENABLED(CONFIG_XFS_RT) && xfs_has_zoned(mp)) { - /* .../xfs//zoned/ */ - error = xfs_sysfs_init(&mp->m_zoned_kobj, &xfs_zoned_ktype, - &mp->m_kobj, "zoned"); - if (error) - goto out_remove_error_dir; - } - return 0; out_remove_error_dir: @@ -846,9 +855,6 @@ xfs_mount_sysfs_del( struct xfs_error_cfg *cfg; int i, j; - if (IS_ENABLED(CONFIG_XFS_RT) && xfs_has_zoned(mp)) - xfs_sysfs_del(&mp->m_zoned_kobj); - for (i = 0; i < XFS_ERR_CLASS_MAX; i++) { for (j = 0; j < XFS_ERR_ERRNO_MAX; j++) { cfg = &mp->m_error_cfg[i][j]; diff --git a/fs/xfs/xfs_sysfs.h b/fs/xfs/xfs_sysfs.h index 1622fe80ad3e..25e5f8fae2f3 100644 --- a/fs/xfs/xfs_sysfs.h +++ b/fs/xfs/xfs_sysfs.h @@ -53,6 +53,8 @@ xfs_sysfs_del( } int xfs_mount_sysfs_init(struct xfs_mount *mp); +int xfs_zoned_sysfs_init(struct xfs_mount *mp); +void xfs_zoned_sysfs_del(struct xfs_mount *mp); void xfs_mount_sysfs_del(struct xfs_mount *mp); #endif /* __XFS_SYSFS_H__ */ diff --git a/fs/xfs/xfs_zone_alloc.c b/fs/xfs/xfs_zone_alloc.c index 08d8b34f467e..7d13fa7ab30a 100644 --- a/fs/xfs/xfs_zone_alloc.c +++ b/fs/xfs/xfs_zone_alloc.c @@ -21,6 +21,7 @@ #include "xfs_rtbitmap.h" #include "xfs_rtrmap_btree.h" #include "xfs_zone_alloc.h" +#include "xfs_sysfs.h" #include "xfs_zone_priv.h" #include "xfs_zones.h" #include "xfs_trace.h" @@ -1420,11 +1421,17 @@ xfs_mount_zones( if (error) goto out_free_zone_info; + error = xfs_zoned_sysfs_init(mp); + if (error) + goto out_zone_gc_unmount; + xfs_info(mp, "%u zones of %u blocks (%u max open zones)", mp->m_sb.sb_rgcount, iz.zone_capacity, mp->m_max_open_zones); trace_xfs_zones_mount(mp); return 0; +out_zone_gc_unmount: + xfs_zone_gc_unmount(mp); out_free_zone_info: xfs_free_zone_info(mp->m_zone_info); return error; @@ -1434,6 +1441,7 @@ void xfs_unmount_zones( struct xfs_mount *mp) { + xfs_zoned_sysfs_del(mp); xfs_zone_gc_unmount(mp); xfs_free_zone_info(mp->m_zone_info); } -- 2.43.0