From: Sasha Levin <sashal@kernel.org>
To: linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc: Qu Wenruo <wqu@suse.com>, Ritesh Harjani <riteshh@linux.ibm.com>,
Filipe Manana <fdmanana@suse.com>,
David Sterba <dsterba@suse.com>, Sasha Levin <sashal@kernel.org>,
linux-btrfs@vger.kernel.org
Subject: [PATCH AUTOSEL 4.4 28/35] btrfs: subpage: fix race between prepare_pages() and btrfs_releasepage()
Date: Thu, 9 Sep 2021 08:01:09 -0400 [thread overview]
Message-ID: <20210909120116.150912-28-sashal@kernel.org> (raw)
In-Reply-To: <20210909120116.150912-1-sashal@kernel.org>
From: Qu Wenruo <wqu@suse.com>
[ Upstream commit e0467866198f7f536806f39e5d0d91ae8018de08 ]
[BUG]
When running generic/095, there is a high chance to crash with subpage
data RW support:
assertion failed: PagePrivate(page) && page->private
------------[ cut here ]------------
kernel BUG at fs/btrfs/ctree.h:3403!
Internal error: Oops - BUG: 0 [#1] SMP
CPU: 1 PID: 3567 Comm: fio Tainted: 5.12.0-rc7-custom+ #17
Hardware name: Khadas VIM3 (DT)
Call trace:
assertfail.constprop.0+0x28/0x2c [btrfs]
btrfs_subpage_assert+0x80/0xa0 [btrfs]
btrfs_subpage_set_uptodate+0x34/0xec [btrfs]
btrfs_page_clamp_set_uptodate+0x74/0xa4 [btrfs]
btrfs_dirty_pages+0x160/0x270 [btrfs]
btrfs_buffered_write+0x444/0x630 [btrfs]
btrfs_direct_write+0x1cc/0x2d0 [btrfs]
btrfs_file_write_iter+0xc0/0x160 [btrfs]
new_sync_write+0xe8/0x180
vfs_write+0x1b4/0x210
ksys_pwrite64+0x7c/0xc0
__arm64_sys_pwrite64+0x24/0x30
el0_svc_common.constprop.0+0x70/0x140
do_el0_svc+0x28/0x90
el0_svc+0x2c/0x54
el0_sync_handler+0x1a8/0x1ac
el0_sync+0x170/0x180
Code: f0000160 913be042 913c4000 955444bc (d4210000)
---[ end trace 3fdd39f4cccedd68 ]---
[CAUSE]
Although prepare_pages() calls find_or_create_page(), which returns the
page locked, but in later prepare_uptodate_page() calls, we may call
btrfs_readpage() which will unlock the page before it returns.
This leaves a window where btrfs_releasepage() can sneak in and release
the page, clearing page->private and causing above ASSERT().
[FIX]
In prepare_uptodate_page(), we should not only check page->mapping, but
also PagePrivate() to ensure we are still holding the correct page which
has proper fs context setup.
Reported-by: Ritesh Harjani <riteshh@linux.ibm.com>
Tested-by: Ritesh Harjani <riteshh@linux.ibm.com>
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
fs/btrfs/file.c | 13 ++++++++++++-
1 file changed, 12 insertions(+), 1 deletion(-)
diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c
index 2426dc56426f..c917a04118cc 100644
--- a/fs/btrfs/file.c
+++ b/fs/btrfs/file.c
@@ -1307,7 +1307,18 @@ static int prepare_uptodate_page(struct inode *inode,
unlock_page(page);
return -EIO;
}
- if (page->mapping != inode->i_mapping) {
+
+ /*
+ * Since btrfs_readpage() will unlock the page before it
+ * returns, there is a window where btrfs_releasepage() can
+ * be called to release the page.
+ * Here we check both inode mapping and PagePrivate() to
+ * make sure the page was not released.
+ *
+ * The private flag check is essential for subpage as we need
+ * to store extra bitmap using page->private.
+ */
+ if (page->mapping != inode->i_mapping || !PagePrivate(page)) {
unlock_page(page);
return -EAGAIN;
}
--
2.30.2
next prev parent reply other threads:[~2021-09-09 13:19 UTC|newest]
Thread overview: 43+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-09-09 12:00 [PATCH AUTOSEL 4.4 01/35] crypto: mxs-dcp - Use sg_mapping_iter to copy data Sasha Levin
2021-09-09 12:00 ` [PATCH AUTOSEL 4.4 02/35] PCI: Use pci_update_current_state() in pci_enable_device_flags() Sasha Levin
2021-09-09 12:00 ` [PATCH AUTOSEL 4.4 03/35] iio: dac: ad5624r: Fix incorrect handling of an optional regulator Sasha Levin
2021-09-09 12:00 ` [PATCH AUTOSEL 4.4 04/35] video: fbdev: kyro: fix a DoS bug by restricting user input Sasha Levin
2021-09-09 12:00 ` [PATCH AUTOSEL 4.4 05/35] netlink: Deal with ESRCH error in nlmsg_notify() Sasha Levin
2021-09-09 12:00 ` [PATCH AUTOSEL 4.4 06/35] Smack: Fix wrong semantics in smk_access_entry() Sasha Levin
2021-09-09 12:00 ` [PATCH AUTOSEL 4.4 07/35] usb: host: fotg210: fix the actual_length of an iso packet Sasha Levin
2021-09-09 12:00 ` [PATCH AUTOSEL 4.4 08/35] usb: gadget: u_ether: fix a potential null pointer dereference Sasha Levin
2021-09-09 12:00 ` [PATCH AUTOSEL 4.4 09/35] tty: serial: jsm: hold port lock when reporting modem line changes Sasha Levin
2021-09-09 12:00 ` [PATCH AUTOSEL 4.4 10/35] bpf/tests: Fix copy-and-paste error in double word test Sasha Levin
2021-09-09 12:00 ` [PATCH AUTOSEL 4.4 11/35] bpf/tests: Do not PASS tests without actually testing the result Sasha Levin
2021-09-09 12:00 ` [PATCH AUTOSEL 4.4 12/35] video: fbdev: asiliantfb: Error out if 'pixclock' equals zero Sasha Levin
2021-09-09 12:00 ` [PATCH AUTOSEL 4.4 13/35] video: fbdev: kyro: " Sasha Levin
2021-09-09 12:00 ` [PATCH AUTOSEL 4.4 14/35] video: fbdev: riva: " Sasha Levin
2021-09-09 12:00 ` [PATCH AUTOSEL 4.4 15/35] ipv4: ip_output.c: Fix out-of-bounds warning in ip_copy_addrs() Sasha Levin
2021-09-09 12:00 ` [PATCH AUTOSEL 4.4 16/35] s390/jump_label: print real address in a case of a jump label bug Sasha Levin
2021-09-09 12:00 ` [PATCH AUTOSEL 4.4 17/35] serial: 8250: Define RX trigger levels for OxSemi 950 devices Sasha Levin
2021-09-09 12:00 ` [PATCH AUTOSEL 4.4 18/35] xtensa: ISS: don't panic in rs_init Sasha Levin
2021-09-09 12:01 ` [PATCH AUTOSEL 4.4 19/35] hvsi: don't panic on tty_register_driver failure Sasha Levin
2021-09-09 12:01 ` [PATCH AUTOSEL 4.4 20/35] serial: 8250_pci: make setup_port() parameters explicitly unsigned Sasha Levin
2021-09-09 12:01 ` [PATCH AUTOSEL 4.4 21/35] Bluetooth: skip invalid hci_sync_conn_complete_evt Sasha Levin
2021-09-09 12:01 ` [PATCH AUTOSEL 4.4 22/35] gpu: drm: amd: amdgpu: amdgpu_i2c: fix possible uninitialized-variable access in amdgpu_i2c_router_select_ddc_port() Sasha Levin
2021-09-09 12:01 ` [PATCH AUTOSEL 4.4 23/35] ARM: tegra: tamonten: Fix UART pad setting Sasha Levin
2021-09-09 12:01 ` [PATCH AUTOSEL 4.4 24/35] ACPICA: iASL: Fix for WPBT table with no command-line arguments Sasha Levin
2021-09-10 7:45 ` Pavel Machek
2021-09-11 14:38 ` Sasha Levin
2021-09-13 12:20 ` Rafael J. Wysocki
2021-09-17 19:21 ` Moore, Robert
2021-09-09 12:01 ` [PATCH AUTOSEL 4.4 25/35] rpc: fix gss_svc_init cleanup on failure Sasha Levin
2021-09-09 12:01 ` [PATCH AUTOSEL 4.4 26/35] gfs2: Don't call dlm after protocol is unmounted Sasha Levin
2021-09-09 12:01 ` [PATCH AUTOSEL 4.4 27/35] btrfs: subpage: check if there are compressed extents inside one page Sasha Levin
2021-09-09 13:01 ` David Sterba
2021-09-09 12:01 ` Sasha Levin [this message]
2021-09-09 13:02 ` [PATCH AUTOSEL 4.4 28/35] btrfs: subpage: fix race between prepare_pages() and btrfs_releasepage() David Sterba
2021-09-09 12:01 ` [PATCH AUTOSEL 4.4 29/35] ASoC: intel: atom: Revert PCM buffer address setup workaround again Sasha Levin
2021-09-09 12:07 ` Takashi Iwai
2021-09-12 21:26 ` Sasha Levin
2021-09-09 12:01 ` [PATCH AUTOSEL 4.4 30/35] mmc: rtsx_pci: Fix long reads when clock is prescaled Sasha Levin
2021-09-09 12:01 ` [PATCH AUTOSEL 4.4 31/35] cifs: fix wrong release in sess_alloc_buffer() failed path Sasha Levin
2021-09-09 12:01 ` [PATCH AUTOSEL 4.4 32/35] Revert "USB: xhci: fix U1/U2 handling for hardware with XHCI_INTEL_HOST quirk set" Sasha Levin
2021-09-09 12:01 ` [PATCH AUTOSEL 4.4 33/35] parport: remove non-zero check on count Sasha Levin
2021-09-09 12:01 ` [PATCH AUTOSEL 4.4 34/35] ath9k: fix OOB read ar9300_eeprom_restore_internal Sasha Levin
2021-09-09 12:01 ` [PATCH AUTOSEL 4.4 35/35] net: fix NULL pointer reference in cipso_v4_doi_free Sasha Levin
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