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Junyong Sun 64a97384d4 firmware: fix a double abort case with fw_load_sysfs_fallback
[ Upstream commit bcfbd3523f3c6eea51a74d217a8ebc5463bcb7f4 ]

fw_sysfs_wait_timeout may return err with -ENOENT
at fw_load_sysfs_fallback and firmware is already
in abort status, no need to abort again, so skip it.

This issue is caused by concurrent situation like below:
when thread 1# wait firmware loading, thread 2# may write
-1 to abort loading and wakeup thread 1# before it timeout.
so wait_for_completion_killable_timeout of thread 1# would
return remaining time which is != 0 with fw_st->status
FW_STATUS_ABORTED.And the results would be converted into
err -ENOENT in __fw_state_wait_common and transfered to
fw_load_sysfs_fallback in thread 1#.
The -ENOENT means firmware status is already at ABORTED,
so fw_load_sysfs_fallback no need to get mutex to abort again.
-----------------------------
thread 1#,wait for loading
fw_load_sysfs_fallback
 ->fw_sysfs_wait_timeout
    ->__fw_state_wait_common
       ->wait_for_completion_killable_timeout

in __fw_state_wait_common,
...
93    ret = wait_for_completion_killable_timeout(&fw_st->completion, timeout);
94    if (ret != 0 && fw_st->status == FW_STATUS_ABORTED)
95       return -ENOENT;
96    if (!ret)
97	 return -ETIMEDOUT;
98
99    return ret < 0 ? ret : 0;
-----------------------------
thread 2#, write -1 to abort loading
firmware_loading_store
 ->fw_load_abort
   ->__fw_load_abort
     ->fw_state_aborted
       ->__fw_state_set
         ->complete_all

in __fw_state_set,
...
111    if (status == FW_STATUS_DONE || status == FW_STATUS_ABORTED)
112       complete_all(&fw_st->completion);
-------------------------------------------
BTW,the double abort issue would not cause kernel panic or create an issue,
but slow down it sometimes.The change is just a minor optimization.

Signed-off-by: Junyong Sun <sunjunyong@xiaomi.com>
Acked-by: Luis Chamberlain <mcgrof@kernel.org>
Link: https://lore.kernel.org/r/1583202968-28792-1-git-send-email-sunjunyong@xiaomi.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2020-04-17 10:50:05 +02:00
arch x86/boot: Use unsigned comparison for addresses 2020-04-17 10:50:03 +02:00
block block: Fix use-after-free issue accessing struct io_cq 2020-04-17 10:50:04 +02:00
certs
crypto
Documentation
drivers firmware: fix a double abort case with fw_load_sysfs_fallback 2020-04-17 10:50:05 +02:00
fs gfs2: Don't demote a glock until its revokes are written 2020-04-17 10:50:03 +02:00
include block: Fix use-after-free issue accessing struct io_cq 2020-04-17 10:50:04 +02:00
init
ipc
kernel genirq/irqdomain: Check pointer in irq_domain_alloc_irqs_hierarchy() 2020-04-17 10:50:04 +02:00
lib
LICENSES
mm
net cfg80211: Do not warn on same channel at the end of CSA 2020-04-17 10:49:59 +02:00
samples
scripts
security
sound
tools selftests/x86/ptrace_syscall_32: Fix no-vDSO segfault 2020-04-17 10:50:02 +02:00
usr
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Linux kernel
============

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In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.