linux/arch/xtensa
Duoming Zhou eb5adc7075 arch: xtensa: platforms: Fix deadlock in rs_close()
There is a deadlock in rs_close(), which is shown
below:

   (Thread 1)              |      (Thread 2)
                           | rs_open()
rs_close()                 |  mod_timer()
 spin_lock_bh() //(1)      |  (wait a time)
 ...                       | rs_poll()
 del_timer_sync()          |  spin_lock() //(2)
 (wait timer to stop)      |  ...

We hold timer_lock in position (1) of thread 1 and
use del_timer_sync() to wait timer to stop, but timer handler
also need timer_lock in position (2) of thread 2.
As a result, rs_close() will block forever.

This patch deletes the redundant timer_lock in order to
prevent the deadlock. Because there is no race condition
between rs_close, rs_open and rs_poll.

Signed-off-by: Duoming Zhou <duoming@zju.edu.cn>
Message-Id: <20220407154430.22387-1-duoming@zju.edu.cn>
Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
2022-04-13 03:36:34 -07:00
..
boot xtensa: fix DTC warning unit_address_format 2022-03-17 02:55:47 -07:00
configs rcu: Fix undefined Kconfig macros 2021-09-13 16:32:46 -07:00
include TTY/Serial driver changes for 5.18-rc1 2022-03-28 13:00:51 -07:00
kernel xtensa: patch_text: Fixup last cpu should be master 2022-04-13 03:36:34 -07:00
lib xtensa: add helpers for division, remainder and shifts 2022-03-09 14:02:40 -08:00
mm xtensa: define update_mmu_tlb function 2022-03-22 09:45:09 -07:00
platforms arch: xtensa: platforms: Fix deadlock in rs_close() 2022-04-13 03:36:34 -07:00
variants
Kbuild xtensa: move core-y in arch/xtensa/Makefile to arch/xtensa/Kbuild 2021-08-11 11:37:13 -07:00
Kconfig dma-mapping updates for Linux 5.18 2022-03-29 08:50:14 -07:00
Kconfig.debug xtensa: make stack dump size configurable 2019-11-26 11:33:39 -08:00
Makefile xtensa: add kernel ABI selection to Kconfig 2022-03-09 14:16:35 -08:00