[PATCH] ide: Fix crash on repeated reset

Michal Miroslaw reported a problem (bugzilla #7023) where a user initiated
reset while the IDE layer was already resetting the channel caused a crash,
and provided a rough fix.

This is a slightly cleaner version of the fix which tracks the reset state
and blocks further reset requests while a reset is in progress.

Note this is not a security issue - random end users can't access the
ioctl in question anyway.

Signed-off-by: Alan Cox <alan@redhat.com>
Cc: Michal Miroslaw <mirq-linux@rere.qmqm.pl>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

3 files changed, 12 insertions, 0 deletions

diff --git a/drivers/ide/ide-iops.c b/drivers/ide/ide-iops.c
index 77703acaec17..badde6331775 100644
--- a/drivers/ide/ide-iops.c
+++ b/drivers/ide/ide-iops.c
@@ -998,6 +998,7 @@ static ide_startstop_t atapi_reset_pollfunc (ide_drive_t *drive)
         }
         /* done polling */
         hwgroup->polling = 0;
+        hwgroup->resetting = 0;
         return ide_stopped;
 }
 
@@ -1057,6 +1058,7 @@ static ide_startstop_t reset_pollfunc (ide_drive_t *drive)
                 }
         }
         hwgroup->polling = 0;   /* done polling */
+        hwgroup->resetting = 0; /* done reset attempt */
         return ide_stopped;
 }
 
@@ -1143,6 +1145,7 @@ static ide_startstop_t do_reset1 (ide_drive_t *drive, int do_not_try_atapi)
 
         /* For an ATAPI device, first try an ATAPI SRST. */
         if (drive->media != ide_disk && !do_not_try_atapi) {
+                hwgroup->resetting = 1;
                 pre_reset(drive);
                 SELECT_DRIVE(drive);
                 udelay (20);
@@ -1168,6 +1171,7 @@ static ide_startstop_t do_reset1 (ide_drive_t *drive, int do_not_try_atapi)
                 return ide_stopped;
         }
 
+        hwgroup->resetting = 1;
         /*
          * Note that we also set nIEN while resetting the device,
          * to mask unwanted interrupts from the interface during the reset.
diff --git a/drivers/ide/ide.c b/drivers/ide/ide.c
index 97b162ca9885..287a66201150 100644
--- a/drivers/ide/ide.c
+++ b/drivers/ide/ide.c
@@ -1364,6 +1364,11 @@ int generic_ide_ioctl(ide_drive_t *drive, struct file *file, struct block_device
 
                         spin_lock_irqsave(&ide_lock, flags);
 
+                        if (HWGROUP(drive)->resetting) {
+                                spin_unlock_irqrestore(&ide_lock, flags);
+                                return -EBUSY;
+                        }
+
                         ide_abort(drive, "drive reset");
 
                         BUG_ON(HWGROUP(drive)->handler);
diff --git a/include/linux/ide.h b/include/linux/ide.h
index a9a9e33e448f..07d8d725541f 100644
--- a/include/linux/ide.h
+++ b/include/linux/ide.h
@@ -825,6 +825,9 @@ typedef struct hwgroup_s {
         unsigned int sleeping   : 1;
                 /* BOOL: polling active & poll_timeout field valid */
         unsigned int polling    : 1;
+                /* BOOL: in a polling reset situation. Must not trigger another reset yet */
+        unsigned int resetting  : 1;
+
                 /* current drive */
         ide_drive_t *drive;
                 /* ptr to current hwif in linked-list */