Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759055Ab2EXUGA (ORCPT ); Thu, 24 May 2012 16:06:00 -0400 Received: from li42-95.members.linode.com ([209.123.162.95]:51253 "EHLO li42-95.members.linode.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933458Ab2EXUF4 (ORCPT ); Thu, 24 May 2012 16:05:56 -0400 From: Pantelis Antoniou To: linux-kernel@vger.kernel.org Cc: linux@arm.linux.org.uk, Russ.Dill@ti.com, mporter@ti.com, linux-arm-kernel@lists.infradead.org, Pantelis Antoniou , stable@vger.kernel.org Subject: [PATCH] [ARM] Unconditional call to smp_cross_call on UP crashes (take #2) Date: Fri, 25 May 2012 19:58:36 +0000 Message-Id: <1337975916-31167-1-git-send-email-panto@antoniou-consulting.com> X-Mailer: git-send-email 1.7.1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3384 Lines: 75 omap2plus_defconfig builds with SMP & SMP_ON_UP set. On beagle (which is UP) is_smp() returns false and we don't call smp_init_cpus which in turn does not initialize smp_cross_call which remains NULL. When issuing a reboot we OOPS with a NULL dereference on stop smp_call. Fixed by a check with if (!cpumask_empty(&mask)) before issuing the smp stop cross call. Restarting system. Unable to handle kernel NULL pointer dereference at virtual address 00000000 pgd = dda50000 [00000000] *pgd=9e723831, *pte=00000000, *ppte=00000000 Internal error: Oops: 80000007 [#1] SMP ARM Modules linked in: CPU: 0 Not tainted (3.4.0-00001-gb15b046 #30) PC is at 0x0 LR is at smp_send_stop+0x4c/0xe8 pc : [<00000000>] lr : [] psr: 60000013 sp : de7b5e70 ip : 00000000 fp : 00000001 r10: 00000000 r9 : de7b4000 r8 : c07263d0 r7 : 00000000 r6 : c06e1294 r5 : 000f4240 r4 : de7b5e74 r3 : 00000000 r2 : 00000000 r1 : 00000006 r0 : de7b5e74 Flags: nZCv IRQs on FIQs on Mode SVC_32 ISA ARM Segment user Control: 10c5387d Table: 9da50019 DAC: 00000015 Process reboot (pid: 2229, stack limit = 0xde7b42f8) Stack: (0xde7b5e70 to 0xde7b6000) 5e60: 00000000 00000000 00000000 01234567 5e80: de7b4000 c001475c 4321fedc c0052570 0000003e 00000000 c081db78 0000003e 5ea0: 00000001 00000002 00000002 c00891f0 00000002 dd5ba0ac 00000002 00000000 5ec0: dd5ba0ac de7b4000 c009eef4 de7b4000 c00f44dc de7b4000 c00f44dc 00000000 5ee0: c0c94d24 de7b4000 00000000 00000000 00000002 00000002 00000000 c00891f0 5f00: 00000002 00000000 00000000 c011286c 00000000 dd5ba060 60000013 00000000 5f20: dd688d8c 00000000 de7b4000 c06e20f8 dec14760 dec14750 de7b4000 c06e20f8 5f40: 00011f10 c01128a0 00000002 00000000 c011286c c00fa014 dd8c3180 de7b4000 5f60: c0013380 de508bc0 00000001 60000010 00000001 ef000000 00000001 c0089bfc 5f80: 00000000 00000001 00000004 00000058 00000000 00000001 00000004 00000058 5fa0: c0013428 c0013260 00000000 00000001 fee1dead 28121969 01234567 00000000 5fc0: 00000000 00000001 00000004 00000058 00000001 00000001 00000000 00000001 5fe0: b6e76200 beba4c90 00009210 b6e76218 60000010 fee1dead 00000000 00000000 [] (smp_send_stop+0x4c/0xe8) from [] (machine_restart+0xc/0x54) [] (machine_restart+0xc/0x54) from [] (sys_reboot+0x140/0x204) [] (sys_reboot+0x140/0x204) from [] (ret_fast_syscall+0x0/0x3c) Code: bad PC value ---[ end trace f5035e8726d1f51b ]--- Signed-off-by: Pantelis Antoniou Cc: stable@vger.kernel.org --- arch/arm/kernel/smp.c | 3 ++- 1 files changed, 2 insertions(+), 1 deletions(-) diff --git a/arch/arm/kernel/smp.c b/arch/arm/kernel/smp.c index 8f46446..7babc3f 100644 --- a/arch/arm/kernel/smp.c +++ b/arch/arm/kernel/smp.c @@ -590,7 +590,8 @@ void smp_send_stop(void) cpumask_copy(&mask, cpu_online_mask); cpumask_clear_cpu(smp_processor_id(), &mask); - smp_cross_call(&mask, IPI_CPU_STOP); + if (!cpumask_empty(&mask)) + smp_cross_call(&mask, IPI_CPU_STOP); /* Wait up to one second for other CPUs to stop */ timeout = USEC_PER_SEC; -- 1.7.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/