From: Paul Fulghum Date: Tue, 11 Apr 2006 05:54:18 +0000 (-0700) Subject: [PATCH] ptmx: fix duplicate idr_remove X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=9453a5adaf32aa0b31d1491819a083d403f645c1;p=GitHub%2FLineageOS%2Fandroid_kernel_samsung_universal7580.git [PATCH] ptmx: fix duplicate idr_remove Remove duplicate call to idr_remove() in ptmx_open. Error during open can result in call to release_dev() followed by call to idr_remove(). release_dev already calls idr_remove so the second call can cause a stack dump in idr_remove()->sub_remove() flagging an attempt to release an already released entry. I reproduces this on a machine with a misconfigured X server (attempting to restart multiple times rapidly) getting the same error as the 1st link below. This also seems to be related to: http://marc.theaimsgroup.com/?l=selinux&m=110536513426735&w=2 http://marc.theaimsgroup.com/?l=selinux&m=110596994916785&w=2 The stack dump can occur on close (as well as open) as shown in the 1st instance above, possible from something like: process A - open (index=0), open fail to out1, release_dev calls idr_remove (index 0), down(sem) sleeps process B - open (index=0), open OK (idr allocated) process A - wake and call idr_remove on index 0 ... process B - close, release_dev, stack dump on idr_remove (index=0) because entry already removed Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- diff --git a/drivers/char/tty_io.c b/drivers/char/tty_io.c index 6f58cacec34..b1f9a1582dd 100644 --- a/drivers/char/tty_io.c +++ b/drivers/char/tty_io.c @@ -2195,6 +2195,7 @@ static int ptmx_open(struct inode * inode, struct file * filp) return 0; out1: release_dev(filp); + return retval; out: down(&allocated_ptys_lock); idr_remove(&allocated_ptys, index);