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authorJia-Ju Bai <baijiaju1990@gmail.com>2019-12-19 11:20:23 +0800
committerMiquel Raynal <miquel.raynal@bootlin.com>2020-01-27 16:55:02 +0100
commit2a0b390b472b7be8909beb77d47db361b613cdc8 (patch)
tree4848ab61e26d6d58c9da2e07afb3b0d411fc9570 /drivers/mtd/maps
parente42617b825f8073569da76dc4510bfa019b1c35a (diff)
mtd: maps: pcmciamtd: fix possible sleep-in-atomic-context bugs in pcmciamtd_set_vpp()
The driver may sleep while holding a spinlock. The function call path (from bottom to top) in Linux 4.19 is: drivers/pcmcia/pcmcia_resource.c, 312: mutex_lock in pcmcia_fixup_vpp drivers/mtd/maps/pcmciamtd.c, 309: pcmcia_fixup_vpp in pcmciamtd_set_vpp drivers/mtd/maps/pcmciamtd.c, 306: _raw_spin_lock_irqsave in pcmciamtd_set_vpp drivers/pcmcia/pcmcia_resource.c, 312: mutex_lock in pcmcia_fixup_vpp drivers/mtd/maps/pcmciamtd.c, 312: pcmcia_fixup_vpp in pcmciamtd_set_vpp drivers/mtd/maps/pcmciamtd.c, 306: _raw_spin_lock_irqsave in pcmciamtd_set_vp mutex_lock() may sleep at runtime. To fix these bugs, the spinlock is replaced with a mutex. These bugs are found by a static analysis tool STCheck written by myself. Signed-off-by: Jia-Ju Bai <baijiaju1990@gmail.com> Reviewed-by: Dominik Brodowski <linux@dominikbrodowski.net> Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Diffstat (limited to 'drivers/mtd/maps')
-rw-r--r--drivers/mtd/maps/pcmciamtd.c7
1 files changed, 3 insertions, 4 deletions
diff --git a/drivers/mtd/maps/pcmciamtd.c b/drivers/mtd/maps/pcmciamtd.c
index 70bb403f69f7..2ac79e1cedd9 100644
--- a/drivers/mtd/maps/pcmciamtd.c
+++ b/drivers/mtd/maps/pcmciamtd.c
@@ -294,16 +294,15 @@ static void pcmcia_copy_to(struct map_info *map, unsigned long to, const void *f
}
-static DEFINE_SPINLOCK(pcmcia_vpp_lock);
+static DEFINE_MUTEX(pcmcia_vpp_lock);
static int pcmcia_vpp_refcnt;
static void pcmciamtd_set_vpp(struct map_info *map, int on)
{
struct pcmciamtd_dev *dev = (struct pcmciamtd_dev *)map->map_priv_1;
struct pcmcia_device *link = dev->p_dev;
- unsigned long flags;
pr_debug("dev = %p on = %d vpp = %d\n\n", dev, on, dev->vpp);
- spin_lock_irqsave(&pcmcia_vpp_lock, flags);
+ mutex_lock(&pcmcia_vpp_lock);
if (on) {
if (++pcmcia_vpp_refcnt == 1) /* first nested 'on' */
pcmcia_fixup_vpp(link, dev->vpp);
@@ -311,7 +310,7 @@ static void pcmciamtd_set_vpp(struct map_info *map, int on)
if (--pcmcia_vpp_refcnt == 0) /* last nested 'off' */
pcmcia_fixup_vpp(link, 0);
}
- spin_unlock_irqrestore(&pcmcia_vpp_lock, flags);
+ mutex_unlock(&pcmcia_vpp_lock);
}