From: Anand Gadiyar To: linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org Cc: Anand Gadiyar , Thomas Gleixner , Ingo Molnar , Russell King Subject: [PATCH RFC] arm: genirq: fix boot on arm platforms Date: Thu, 14 Oct 2010 22:59:57 +0530 Message-Id: <1287077397-21781-1-git-send-email-gadiyar@ti.com> X-Mailer: git-send-email 1.5.6.6 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit b683de2b3 in linux-next as of 20101014 (genirq: Query arch for number of early descriptors) seems to have broken bootup on several ARM boards - my beagleboard gives the following dump with earlyprintk. NR_IRQS:402 Unable to handle kernel NULL pointer dereference at virtual address 00000028 pgd = c0004000 [00000028] *pgd=00000000 Internal error: Oops: 5 [#1] last sysfs file: Modules linked in: CPU: 0 Not tainted (2.6.36-rc7-next-20101014-linux-next-20101012+ #40) PC is at init_IRQ+0x14/0x48 LR is at start_kernel+0x150/0x2c0 pc : [] lr : [] psr: 800001d3 sp : c0927fd0 ip : 000008d0 fp : 00000000 r10: 00000000 r9 : 411fc083 r8 : 8002ca24 r7 : c092a80c r6 : c0439c44 r5 : c0439c48 r4 : c0979ac0 r3 : 00000001 r2 : 00000000 r1 : 00000001 r0 : 00000000 Flags: Nzcv IRQs off FIQs off Mode SVC_32 ISA ARM Segment kernel Control: 10c5387f Table: 80004019 DAC: 00000015 Process swapper (pid: 0, stack limit = 0xc09262f0) Stack: (0xc0927fd0 to 0xc0928000) 7fc0: 00000192 c0008944 c00085bc 00000000 7fe0: 00000000 c0439c48 00000000 10c5387d c0979c5c 80008034 00000000 00000000 [] (init_IRQ+0x14/0x48) from [] (start_kernel+0x150/0x2c0) [] (start_kernel+0x150/0x2c0) from [<80008034>] (0x80008034) Code: e3a03000 ea000004 e3a02000 e2833001 (e5921028) ---[ end trace 1b75b31a2719ed1c ]--- Kernel panic - not syncing: Attempted to kill the idle task! We seem to be using desc->status without assigning desc to anything. Fix this by adding back the code that was originally there. Signed-off-by: Anand Gadiyar Cc: Thomas Gleixner Cc: Ingo Molnar Cc: Russell King --- I'm not 100% sure this is the correct fix. I'm just reporting that this small change allows me to boot again. Apologies if some of you get this twice - a typo in git-send-email caused the mail to bounce from some accounts, so I'm resending. arch/arm/kernel/irq.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) Index: mainline/arch/arm/kernel/irq.c =================================================================== --- mainline.orig/arch/arm/kernel/irq.c +++ mainline/arch/arm/kernel/irq.c @@ -157,8 +157,10 @@ void __init init_IRQ(void) struct irq_desc *desc; int irq; - for (irq = 0; irq < nr_irqs; irq++) + for (irq = 0; irq < nr_irqs; irq++) { + desc = irq_to_desc_alloc_node(irq, 0); desc->status |= IRQ_NOREQUEST | IRQ_NOPROBE; + } init_arch_irq(); }