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| author |   Jia-Ju Bai <baijiaju1990@gmail.com> | 2019-12-19 11:20:23 +0800 |
|---|---|---|
| committer |   Miquel Raynal <miquel.raynal@bootlin.com> | 2020-01-27 16:55:02 +0100 |
| commit | 2a0b390b472b7be8909beb77d47db361b613cdc8 (patch) | |
| tree | 4848ab61e26d6d58c9da2e07afb3b0d411fc9570 /drivers/mtd | |
| parent | Linux 5.5-rc1 (diff) | |
| download | linux-dev-2a0b390b472b7be8909beb77d47db361b613cdc8.tar.xz linux-dev-2a0b390b472b7be8909beb77d47db361b613cdc8.zip | |
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')
| -rw-r--r-- | drivers/mtd/maps/pcmciamtd.c | 7 |
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); } |