On Wed 2018-06-27 23:16:12, Sergey Senozhatsky wrote:
On (06/27/18 16:08), Petr Mladek wrote:
The commit 719f6a7040f1bdaf96 ("printk: Use the main logbuf in NMI when logbuf_lock is available") brought back the possible deadlocks in printk() and NMI.
This is rework of the proposed fix, see https://lkml.kernel.org/r/20180606111557.xzs6l3lkvg7lq3ts@pathway.suse.cz
Grr, the right link is https://lkml.kernel.org/r/20180608104825.e7xoxteelaxnwx66@pathway.suse.cz
I realized that we could rather easily move the check to vprintk_func() and still avoid any race. I believe that this is a win-win solution.
Changes against v1:
- Move the check from vprintk_emit() to vprintk_func()
- More straightforward commit message
- Fix build with CONFIG_PRINTK_NMI disabled
Did I miss out V1?
It is the above fixed link. I am sorry for the confusion.
Petr Mladek (3): printk: Split the code for storing a message into the log buffer printk: Create helper function to queue deferred console handling printk/nmi: Prevent deadlock when accessing the main log buffer in NMI
Patch 3/3 is not in my mailbox, somehow [I checked the spam folder]. I'm not Cc-ed or the message got lost somewhere before it reached my gmail?
Ah, the following line somehow confused git send-mail and the message had broken list of recipients:
Cc: stable@vger.kernel.org # 4.13+
I have sent it once again as you have already noticed.
Best Regards, Petr