From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: linux-kernel@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
stable@vger.kernel.org,
Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>,
Tejun Heo <tj@kernel.org>,
syzbot <syzbot+9873874c735f2892e7e9@syzkaller.appspotmail.com>,
Dave Chinner <dchinner@redhat.com>, Jan Kara <jack@suse.cz>,
Jens Axboe <axboe@kernel.dk>
Subject: [PATCH 4.9 13/36] bdi: Fix oops in wb_workfn()
Date: Mon, 14 May 2018 08:48:47 +0200 [thread overview]
Message-ID: <20180514064805.274404524@linuxfoundation.org> (raw)
In-Reply-To: <20180514064804.252823817@linuxfoundation.org>
4.9-stable review patch. If anyone has any objections, please let me know.
------------------
From: Jan Kara <jack@suse.cz>
commit b8b784958eccbf8f51ebeee65282ca3fd59ea391 upstream.
Syzbot has reported that it can hit a NULL pointer dereference in
wb_workfn() due to wb->bdi->dev being NULL. This indicates that
wb_workfn() was called for an already unregistered bdi which should not
happen as wb_shutdown() called from bdi_unregister() should make sure
all pending writeback works are completed before bdi is unregistered.
Except that wb_workfn() itself can requeue the work with:
mod_delayed_work(bdi_wq, &wb->dwork, 0);
and if this happens while wb_shutdown() is waiting in:
flush_delayed_work(&wb->dwork);
the dwork can get executed after wb_shutdown() has finished and
bdi_unregister() has cleared wb->bdi->dev.
Make wb_workfn() use wakeup_wb() for requeueing the work which takes all
the necessary precautions against racing with bdi unregistration.
CC: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
CC: Tejun Heo <tj@kernel.org>
Fixes: 839a8e8660b6777e7fe4e80af1a048aebe2b5977
Reported-by: syzbot <syzbot+9873874c735f2892e7e9@syzkaller.appspotmail.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
fs/fs-writeback.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--- a/fs/fs-writeback.c
+++ b/fs/fs-writeback.c
@@ -1942,7 +1942,7 @@ void wb_workfn(struct work_struct *work)
}
if (!list_empty(&wb->work_list))
- mod_delayed_work(bdi_wq, &wb->dwork, 0);
+ wb_wakeup(wb);
else if (wb_has_dirty_io(wb) && dirty_writeback_interval)
wb_wakeup_delayed(wb);
next prev parent reply other threads:[~2018-05-14 6:48 UTC|newest]
Thread overview: 41+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-05-14 6:48 [PATCH 4.9 00/36] 4.9.100-stable review Greg Kroah-Hartman
2018-05-14 6:48 ` [PATCH 4.9 01/36] ipvs: fix rtnl_lock lockups caused by start_sync_thread Greg Kroah-Hartman
2018-05-14 6:48 ` [PATCH 4.9 02/36] IB/device: Convert ib-comp-wq to be CPU-bound Greg Kroah-Hartman
2018-05-14 6:48 ` [PATCH 4.9 03/36] kcm: Call strp_stop before strp_done in kcm_attach Greg Kroah-Hartman
2018-05-14 6:48 ` [PATCH 4.9 04/36] crypto: af_alg - fix possible uninit-value in alg_bind() Greg Kroah-Hartman
2018-05-14 6:48 ` [PATCH 4.9 05/36] netlink: fix uninit-value in netlink_sendmsg Greg Kroah-Hartman
2018-05-14 6:48 ` [PATCH 4.9 06/36] net: fix rtnh_ok() Greg Kroah-Hartman
2018-05-14 6:48 ` [PATCH 4.9 07/36] net: initialize skb->peeked when cloning Greg Kroah-Hartman
2018-05-14 6:48 ` [PATCH 4.9 08/36] net: fix uninit-value in __hw_addr_add_ex() Greg Kroah-Hartman
2018-05-14 6:48 ` [PATCH 4.9 09/36] dccp: initialize ireq->ir_mark Greg Kroah-Hartman
2018-05-14 6:48 ` [PATCH 4.9 10/36] soreuseport: initialise timewait reuseport field Greg Kroah-Hartman
2018-05-14 6:48 ` [PATCH 4.9 11/36] perf: Remove superfluous allocation error check Greg Kroah-Hartman
2018-05-14 6:48 ` [PATCH 4.9 12/36] tcp: fix TCP_REPAIR_QUEUE bound checking Greg Kroah-Hartman
2018-05-14 6:48 ` Greg Kroah-Hartman [this message]
2018-05-14 6:48 ` [PATCH 4.9 14/36] KVM: PPC: Book3S HV: Fix trap number return from __kvmppc_vcore_entry Greg Kroah-Hartman
2018-05-14 6:48 ` [PATCH 4.9 15/36] f2fs: fix a dead loop in f2fs_fiemap() Greg Kroah-Hartman
2018-05-14 6:48 ` [PATCH 4.9 16/36] arm64: Add work around for Arm Cortex-A55 Erratum 1024718 Greg Kroah-Hartman
2018-05-14 6:48 ` [PATCH 4.9 17/36] gpioib: do not free unrequested descriptors Greg Kroah-Hartman
2018-05-14 6:48 ` [PATCH 4.9 18/36] gpio: fix aspeed_gpio unmask irq Greg Kroah-Hartman
2018-05-14 6:48 ` [PATCH 4.9 19/36] gpio: fix error path in lineevent_create Greg Kroah-Hartman
2018-05-14 6:48 ` [PATCH 4.9 20/36] rfkill: gpio: fix memory leak in probe error path Greg Kroah-Hartman
2018-05-14 6:48 ` [PATCH 4.9 21/36] libata: Apply NOLPM quirk for SanDisk SD7UB3Q*G1001 SSDs Greg Kroah-Hartman
2018-05-14 6:48 ` [PATCH 4.9 22/36] tracing: Fix regex_match_front() to not over compare the test string Greg Kroah-Hartman
2018-05-14 6:48 ` [PATCH 4.9 23/36] can: kvaser_usb: Increase correct stats counter in kvaser_usb_rx_can_msg() Greg Kroah-Hartman
2018-05-14 6:48 ` [PATCH 4.9 24/36] drm/vc4: Fix scaling of uni-planar formats Greg Kroah-Hartman
2018-05-14 6:48 ` [PATCH 4.9 25/36] drm/i915: Fix drm:intel_enable_lvds ERROR message in kernel log Greg Kroah-Hartman
2018-05-14 6:49 ` [PATCH 4.9 26/36] net: atm: Fix potential Spectre v1 Greg Kroah-Hartman
2018-05-14 6:49 ` [PATCH 4.9 27/36] atm: zatm: " Greg Kroah-Hartman
2018-05-14 6:49 ` [PATCH 4.9 28/36] Revert "Bluetooth: btusb: Fix quirk for Atheros 1525/QCA6174" Greg Kroah-Hartman
2018-05-14 6:49 ` [PATCH 4.9 29/36] thermal: exynos: Reading temperature makes sense only when TMU is turned on Greg Kroah-Hartman
2018-05-14 6:49 ` [PATCH 4.9 30/36] thermal: exynos: Propagate error value from tmu_read() Greg Kroah-Hartman
2018-05-14 6:49 ` [PATCH 4.9 31/36] tracing/uprobe_event: Fix strncpy corner case Greg Kroah-Hartman
2018-05-14 6:49 ` [PATCH 4.9 32/36] perf/x86: Fix possible Spectre-v1 indexing for hw_perf_event cache_* Greg Kroah-Hartman
2018-05-14 6:49 ` [PATCH 4.9 33/36] perf/x86/cstate: Fix possible Spectre-v1 indexing for pkg_msr Greg Kroah-Hartman
2018-05-14 6:49 ` [PATCH 4.9 34/36] perf/x86/msr: Fix possible Spectre-v1 indexing in the MSR driver Greg Kroah-Hartman
2018-05-14 6:49 ` [PATCH 4.9 35/36] perf/core: Fix possible Spectre-v1 indexing for ->aux_pages[] Greg Kroah-Hartman
2018-05-14 6:49 ` [PATCH 4.9 36/36] perf/x86: Fix possible Spectre-v1 indexing for x86_pmu::event_map() Greg Kroah-Hartman
2018-05-14 13:05 ` [PATCH 4.9 00/36] 4.9.100-stable review kernelci.org bot
2018-05-14 16:20 ` Guenter Roeck
2018-05-14 22:03 ` Shuah Khan
2018-05-15 5:40 ` Naresh Kamboju
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