From efe8072316a899294212055c147d3d9adca940a4 Mon Sep 17 00:00:00 2001 From: Tony Lindgren Date: Mon, 21 Apr 2014 19:26:13 -0700 Subject: [PATCH] ARM: OMAP2+: Fix oops for GPMC free If gpmc_cs_remap() fails we will get an error because we are calling release_resource() on an uninitialized resource. Let's fix that by checking the resource flags. And while at it, let's also make gpmc_cs_delete_mem() use the res pointer that we already have to avoid confusion. Without this patch we can get the following error: omap-gpmc 6e000000.gpmc: cannot remap GPMC CS 1 to 0x01000300 Unable to handle kernel NULL pointer dereference at virtual address 00000018 ... (gpmc_cs_free+0x94/0xc8) (gpmc_probe_generic_child+0x178/0x1ec) (gpmc_probe_dt+0x1bc/0x2cc) (gpmc_probe+0x250/0x44c) (platform_drv_probe+0x3c/0x6c) (really_probe+0x74/0x208) (driver_probe_device+0x34/0x50) (bus_for_each_drv+0x60/0x8c) (device_attach+0x80/0xa4) (bus_probe_device+0x88/0xb0) (device_add+0x320/0x450) (of_platform_device_create_pdata+0x80/0x9c) (of_platform_bus_create+0xd0/0x170) (of_platform_bus_create+0x12c/0x170) (of_platform_populate+0x60/0x98) (pdata_quirks_init+0x30/0x48) (customize_machine+0x20/0x48) (do_one_initcall+0x2c/0x14c) (do_basic_setup+0x98/0xd8) (kernel_init_freeable+0x12c/0x1e0) (kernel_init+0x8/0xf0) (ret_from_fork+0x14/0x2c) Code: e1a04000 e59f0070 eb195136 e5942010 (e5923018) Cc: Pekon Gupta Reviewed-by: Javier Martinez Canillas Signed-off-by: tony Lindgren --- arch/arm/mach-omap2/gpmc.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/arch/arm/mach-omap2/gpmc.c b/arch/arm/mach-omap2/gpmc.c index ab43755364f5..84e57e6fbc26 100644 --- a/arch/arm/mach-omap2/gpmc.c +++ b/arch/arm/mach-omap2/gpmc.c @@ -501,7 +501,7 @@ static int gpmc_cs_delete_mem(int cs) int r; spin_lock(&gpmc_mem_lock); - r = release_resource(&gpmc_cs_mem[cs]); + r = release_resource(res); res->start = 0; res->end = 0; spin_unlock(&gpmc_mem_lock); @@ -586,6 +586,8 @@ EXPORT_SYMBOL(gpmc_cs_request); void gpmc_cs_free(int cs) { + struct resource *res = &gpmc_cs_mem[cs]; + spin_lock(&gpmc_mem_lock); if (cs >= gpmc_cs_num || cs < 0 || !gpmc_cs_reserved(cs)) { printk(KERN_ERR "Trying to free non-reserved GPMC CS%d\n", cs); @@ -594,7 +596,8 @@ void gpmc_cs_free(int cs) return; } gpmc_cs_disable_mem(cs); - release_resource(&gpmc_cs_mem[cs]); + if (res->flags) + release_resource(res); gpmc_cs_set_reserved(cs, 0); spin_unlock(&gpmc_mem_lock); } -- 2.30.2