On 2019/12/19 1:28, Dominik Brodowski wrote:
On Wed, Dec 18, 2019 at 10:05:52PM +0800, Jia-Ju Bai wrote:
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.
Thanks for noticing this issue.
To fix these bugs, pcmcia_fixup_vpp() is called without holding the
spinlock.
I don't think that this is the right approach here -- we lose the protection
against races in calls to pcmcia_fixup_vpp(). Instead, we should change the
spinlock to a mutex, which seems to be sufficient here. Could you prepare
such a patch, please?
Okay, thanks for the advice :)
I will send a new patch.
Best wishes,
Jia-Ju Bai
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