Messages in this thread | | | Date | Mon, 29 Nov 2010 23:41:45 +0100 | From | Jiri Slaby <> | Subject | Re: [PATCH 1/2] TTY: ldisc, fix open flag handling |
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On 11/29/2010 10:50 PM, Greg KH wrote: > On Thu, Nov 25, 2010 at 12:27:54AM +0100, Jiri Slaby wrote: >> When a concrete ldisc open fails in tty_ldisc_open, we forget to clear >> TTY_LDISC_OPEN. This causes a false warning on the next ldisc open: >> WARNING: at drivers/char/tty_ldisc.c:445 tty_ldisc_open+0x26/0x38() >> Hardware name: System Product Name >> Modules linked in: ... >> Pid: 5251, comm: a.out Tainted: G W 2.6.32-5-686 #1 >> Call Trace: >> [<c1030321>] ? warn_slowpath_common+0x5e/0x8a >> [<c1030357>] ? warn_slowpath_null+0xa/0xc >> [<c119311c>] ? tty_ldisc_open+0x26/0x38 >> [<c11936c5>] ? tty_set_ldisc+0x218/0x304 >> ... >> >> So clear the bit when failing... >> >> Introduced in c65c9bc3efa (tty: rewrite the ldisc locking) back in >> 2.6.31-rc1. >> >> Signed-off-by: Jiri Slaby <jslaby@suse.cz> >> Cc: Alan Cox <alan@linux.intel.com> >> Reported-by: Sergey Lapin <slapin@ossfans.org> >> Tested-by: Sergey Lapin <slapin@ossfans.org> > > Is this still needed, or can I just use your: > [PATCH v2 1/2] TTY: don't allow reopen when ldisc is changing > patch instead?
This patch is still needed, it fixes a fail path.
Other than that there are 3 races in 2.6.36, one of them is introduced in 2.6.36, the rest in 2.6.32. For each bug there is a single patch I sent: * TTY: open/hangup race fixup - introduced in 2.6.36 - open vs hangup race * TTY: don't allow reopen when ldisc is changing - tiocsetd vs open race * TTY: ldisc, fix open flag handling - this you are asking about - when ldisc->open fails, we blow up * Char: TTY, restore tty_ldisc_wait_idle - this is in 37-rc2 already - multiple opens followed by tiocsetd blows the machine up
All of them are stable candidates (but I would give them some time in HEAD to see if something breaks, since I opened a can of worms). The first one is applicable only to 2.6.36 indeed.
thanks, -- js suse labs
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