On Mon, 10 Apr 2023 21:08:26 +0800 Baokun Li libaokun1@huawei.com wrote:
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To solve this problem, percpu_ref_exit() is called under RCU protection to avoid race between cgwb_release_workfn() and bdi_split_work_to_wbs(). Moreover, replace wb_get() with wb_tryget() in bdi_split_work_to_wbs(), and skip the current wb if wb_tryget() fails because the wb has already been shutdown.
Fixes: b817525a4a80 ("writeback: bdi_writeback iteration must not skip dying ones") Fixes: f3b6a6df38aa ("writeback, cgroup: keep list of inodes attached to bdi_writeback")
Two Fixes: is awkward. The Fixes: serves a guide to which kernel versions should be patched, but those two commits are six years apart.
So... how far back should this fix be backported?
fs/fs-writeback.c | 17 ++++++++++------- mm/backing-dev.c | 12 ++++++++++--
Jens, which tree do you think should carry this?