On 02/08/2015 05:02 PM, Robert Jarzmik wrote: > As the devicetree binding doesn't require num_cs to exist or be strictly > positive, and neither does the platform data case, a bug appear when > num_cs is set to 0 and panics the kernel. > > The issue is that in alloc_nand_resource(), chip is dereferenced without > having a value assigned when num_cs == 0. > > Fix this by returning ENODEV is num_cs == 0. > > The panic seen is : > Unable to handle kernel NULL pointer dereference at virtual address 000002b8 > pgd = c0004000 > [000002b8] *pgd=00000000 > Internal error: Oops: 5 [#1] PREEMPT ARM > Modules linked in: > Hardware name: Marvell PXA3xx (Device Tree Support) > task: c3822aa0 ti: c3826000 task.ti: c3826000 > PC is at alloc_nand_resource+0x180/0x4a8 > LR is at alloc_nand_resource+0xa0/0x4a8 > pc : [<c0275b90>] lr : [<c0275ab0>] psr: 68000013 > sp : c3827d90 ip : 00000000 fp : 00000000 > r10: c3862200 r9 : 0000005e r8 : 00000000 > r7 : c3865610 r6 : c3862210 r5 : c3924210 r4 : c3862200 > r3 : 00000000 r2 : 00000000 r1 : 00000000 r0 : 00000000 > Flags: nZCv IRQs on FIQs on Mode SVC_32 ISA ARM Segment kernel > Control: 0000397f Table: 80004018 DAC: 00000035 > Process swapper (pid: 1, stack limit = 0xc3826198) > Stack: (0xc3827d90 to 0xc3828000) > ...zip... > [<c0275b90>] (alloc_nand_resource) from [<c0275ff8>] > (pxa3xx_nand_probe+0x140/0x978) > [<c0275ff8>] (pxa3xx_nand_probe) from [<c0258c40>] > (platform_drv_probe+0x48/0xa4) > [<c0258c40>] (platform_drv_probe) from [<c0257650>] > (driver_probe_device+0x80/0x21c) > [<c0257650>] (driver_probe_device) from [<c0257878>] > (__driver_attach+0x8c/0x90) > [<c0257878>] (__driver_attach) from [<c0255ec4>] (bus_for_each_dev+0x58/0x88) > [<c0255ec4>] (bus_for_each_dev) from [<c0256ec8>] (bus_add_driver+0xd8/0x1d4) > [<c0256ec8>] (bus_add_driver) from [<c0257f14>] (driver_register+0x78/0xf4) > [<c0257f14>] (driver_register) from [<c00088a8>] (do_one_initcall+0x80/0x1e4) > [<c00088a8>] (do_one_initcall) from [<c048ed08>] > (kernel_init_freeable+0xec/0x1b4) > [<c048ed08>] (kernel_init_freeable) from [<c0377d8c>] (kernel_init+0x8/0xe4) > [<c0377d8c>] (kernel_init) from [<c00095f8>] (ret_from_fork+0x14/0x3c) > Code: e503b234 e5953008 e1530001 caffffd1 (e59002b8) > ---[ end trace a5770060c8441895 ]--- > > Signed-off-by: Robert Jarzmik <[email protected]> > --- > drivers/mtd/nand/pxa3xx_nand.c | 2 ++ > 1 file changed, 2 insertions(+) > > diff --git a/drivers/mtd/nand/pxa3xx_nand.c b/drivers/mtd/nand/pxa3xx_nand.c > index 96b0b1d..4a2df63 100644 > --- a/drivers/mtd/nand/pxa3xx_nand.c > +++ b/drivers/mtd/nand/pxa3xx_nand.c > @@ -1572,6 +1572,8 @@ static int alloc_nand_resource(struct platform_device > *pdev) > int ret, irq, cs; > > pdata = dev_get_platdata(&pdev->dev); > + if (pdata->num_cs <= 0) > + return -ENODEV; > info = devm_kzalloc(&pdev->dev, sizeof(*info) + (sizeof(*mtd) + > sizeof(*host)) * pdata->num_cs, GFP_KERNEL); > if (!info) >
Looks good, Acked-by: Ezequiel Garcia <[email protected]> -- Ezequiel García, Free Electrons Embedded Linux, Kernel and Android Engineering http://free-electrons.com -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
