linux-kernel - floppy: Use del_timer

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [day] [month] [year] [list]

Message-ID: <alpine.LFD.2.02.1107231247350.2702@ionos>
Date:	Sat, 23 Jul 2011 12:49:42 +0200 (CEST)
From:	Thomas Gleixner <tglx@...utronix.de>
To:	LKML <linux-kernel@...r.kernel.org>
cc:	Jens Axboe <jaxboe@...ionio.com>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Carsten Emde <C.Emde@...dl.org>
Subject: floppy: Use del_timer_sync() in init cleanup

From: Carsten Emde <C.Emde@...dl.org>

When no floppy is found the module code can be released while a timer
function is pending or about to be executed.

CPU0                                  CPU1
				      floppy_init()
timer_softirq()
   spin_lock_irq(&base->lock);   
   detach_timer();
   spin_unlock_irq(&base->lock);
   -> Interrupt
					del_timer();
				        return -ENODEV;
                                      module_cleanup();
   <- EOI
   call_timer_fn();
   OOPS

Use del_timer_sync() to prevent this.				      

Signed-off-by: Carsten Emde <C.Emde@...dl.org>
Signed-off-by: Thomas Gleixner <tglx@...utronix.de>

---
 drivers/block/floppy.c |    8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

Index: linux-3.0/drivers/block/floppy.c
===================================================================
--- linux-3.0.orig/drivers/block/floppy.c
+++ linux-3.0/drivers/block/floppy.c
@@ -4250,7 +4250,7 @@ static int __init floppy_init(void)
 	use_virtual_dma = can_use_virtual_dma & 1;
 	fdc_state[0].address = FDC1;
 	if (fdc_state[0].address == -1) {
-		del_timer(&fd_timeout);
+		del_timer_sync(&fd_timeout);
 		err = -ENODEV;
 		goto out_unreg_region;
 	}
@@ -4261,7 +4261,7 @@ static int __init floppy_init(void)
 	fdc = 0;		/* reset fdc in case of unexpected interrupt */
 	err = floppy_grab_irq_and_dma();
 	if (err) {
-		del_timer(&fd_timeout);
+		del_timer_sync(&fd_timeout);
 		err = -EBUSY;
 		goto out_unreg_region;
 	}
@@ -4318,7 +4318,7 @@ static int __init floppy_init(void)
 		user_reset_fdc(-1, FD_RESET_ALWAYS, false);
 	}
 	fdc = 0;
-	del_timer(&fd_timeout);
+	del_timer_sync(&fd_timeout);
 	current_drive = 0;
 	initialized = true;
 	if (have_no_fdc) {
@@ -4368,7 +4368,7 @@ out_unreg_blkdev:
 	unregister_blkdev(FLOPPY_MAJOR, "fd");
 out_put_disk:
 	while (dr--) {
-		del_timer(&motor_off_timer[dr]);
+		del_timer_sync(&motor_off_timer[dr]);
 		if (disks[dr]->queue)
 			blk_cleanup_queue(disks[dr]->queue);
 		put_disk(disks[dr]);
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/