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ZhaoLong Wang 0b031f5983 ubi: Fix deadlock caused by recursively holding work_sem

[ Upstream commit f773f0a331d6c41733b17bebbc1b6cae12e016f5 ]

During the processing of the bgt, if the sync_erase() return -EBUSY
or some other error code in __erase_worker(),schedule_erase() called
again lead to the down_read(ubi->work_sem) hold twice and may get
block by down_write(ubi->work_sem) in ubi_update_fastmap(),
which cause deadlock.

          ubi bgt                        other task
 do_work
  down_read(&ubi->work_sem)          ubi_update_fastmap
  erase_worker                         # Blocked by down_read
   __erase_worker                      down_write(&ubi->work_sem)
    schedule_erase
     schedule_ubi_work
      down_read(&ubi->work_sem)

Fix this by changing input parameter @nested of the schedule_erase() to
'true' to avoid recursively acquiring the down_read(&ubi->work_sem).

Also, fix the incorrect comment about @nested parameter of the
schedule_erase() because when down_write(ubi->work_sem) is held, the
@nested is also need be true.

Link: https://bugzilla.kernel.org/show_bug.cgi?id=217093
Fixes: 2e8f08deabbc ("ubi: Fix races around ubi_refill_pools()")
Signed-off-by: ZhaoLong Wang <wangzhaolong1@huawei.com>
Reviewed-by: Zhihao Cheng <chengzhihao1@huawei.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
Signed-off-by: Sasha Levin <sashal@kernel.org>

2023-04-20 12:13:56 +02:00

chips

mtd: cfi_cmdset_0002: Use chip_ready() for write on S29GL064N

2022-06-09 10:23:25 +02:00

devices

mtd: devices: docg3: check the return value of devm_ioremap() in the probe

2022-10-26 12:35:09 +02:00

hyperbus

mtd: hyperbus: rpc-if: fix bug in rpcif_hb_remove

2022-01-27 11:03:15 +01:00

lpddr

mtd: lpddr2_nvm: Fix possible null-ptr-deref