Re: [PATCH] PHYLIB: IRQ event workqueue handling fixes

Maciej W. Rozycki
2007-10-15T17:04:01Z

On Mon, 15 Oct 2007, Jarek Poplawski wrote:

> Could you explain why cancel_work_sync() is better here than
> flush_scheduled_work() wrt. rtnl_lock()?

Well, this is actually the bit that made cancel_work_sync() be written in
the first place. The short story is the netlink lock is most probably
held at this point (depending on the usage of phy_disconnect()) and there
is also an event waiting in the queue that requires the lock, so if
flush_scheduled_work() is called here a deadlock will happen.

Let me find a reference for a longer story...:

http://www.linux-mips.org/cgi-bin/mesg.cgi?a=linux-mips&i=Pine.LNX.4.64N.0610031509380.4642%40blysk.ds.pg.gda.pl

and then discussed again:

http://www.uwsg.indiana.edu/hypermail/linux/kernel/0612.0/0593.html

Maciej