Hi,

current linaro kernel on 13.07 (3.10.1.0-1-linaro-omap) shows stack below.

Full dmesg here: https://dl.dropboxusercontent.com/u/21820416/rcu.stall.panda

Rgds, Chris

[ 4538.880432] INFO: rcu_sched detected stalls on CPUs/tasks: { 1} (detected by 0, t=2103 jiffies, g=1649, c=1648, q=18) [ 4538.891723] Backtrace for cpu 0 (current): [ 4538.891723] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 3.10.1.0-1-linaro-omap #1ubuntu1~ci+130723003933-Ubuntu [ 4538.891754] [<c001175d>] (unwind_backtrace+0x1/0x9c) from [<c000f625>] (show_stack+0x11/0x14) [ 4538.891815] [<c000f625>] (show_stack+0x11/0x14) from [<c00106d5>] (smp_send_all_cpu_backtrace+0x49/0x98) [ 4538.891815] [<c00106d5>] (smp_send_all_cpu_backtrace+0x49/0x98) from [<c007c755>] (rcu_check_callbacks+0x439/0x4ac) [ 4538.891815] [<c007c755>] (rcu_check_callbacks+0x439/0x4ac) from [<c0036599>] (update_process_times+0x2d/0x4c) [ 4538.891876] [<c0036599>] (update_process_times+0x2d/0x4c) from [<c005fcfd>] (tick_sched_handle+0x35/0x40) [ 4538.891906] [<c005fcfd>] (tick_sched_handle+0x35/0x40) from [<c005feed>] (tick_sched_timer+0x31/0x54) [ 4538.891937] [<c005feed>] (tick_sched_timer+0x31/0x54) from [<c004532b>] (__run_hrtimer+0x5b/0x138) [ 4538.891937] [<c004532b>] (__run_hrtimer+0x5b/0x138) from [<c0045bcb>] (hrtimer_interrupt+0xdb/0x22c) [ 4538.891967] [<c0045bcb>] (hrtimer_interrupt+0xdb/0x22c) from [<c0010e13>] (twd_handler+0x1b/0x28) [ 4538.891998] [<c0010e13>] (twd_handler+0x1b/0x28) from [<c00783b9>] (handle_percpu_devid_irq+0x4d/0xac) [ 4538.891998] [<c00783b9>] (handle_percpu_devid_irq+0x4d/0xac) from [<c0075ead>] (generic_handle_irq+0x19/0x24) [ 4538.892028] [<c0075ead>] (generic_handle_irq+0x19/0x24) from [<c000d16d>] (handle_IRQ+0x29/0x68) [ 4538.892059] [<c000d16d>] (handle_IRQ+0x29/0x68) from [<c00084db>] (gic_handle_irq+0x27/0x50) [ 4538.892059] [<c00084db>] (gic_handle_irq+0x27/0x50) from [<c045315b>] (__irq_svc+0x3b/0x5c) [ 4538.892059] Exception stack(0xc06e3f68 to 0xc06e3fb0) [ 4538.892059] 3f60: 00000000 00000000 00000000 00000000 c06e2000 c075f130 [ 4538.892120] 3f80: c06e2000 c075ea93 c075f130 c06ea594 c045c2e0 c06e2000 c0fe5908 c06e3fb0 [ 4538.892120] 3fa0: c007bab1 c0058b48 400f0133 ffffffff [ 4538.892120] [<c045315b>] (__irq_svc+0x3b/0x5c) from [<c0058b48>] (cpu_startup_entry+0xbc/0x164) [ 4538.892120] [<c0058b48>] (cpu_startup_entry+0xbc/0x164) from [<c06735f9>] (start_kernel+0x251/0x2ac) [ 4538.892120] [ 4538.892120] sending IPI to all other CPUs: [ 4538.892211] IPI backtrace for cpu 1 [ 4538.892211] [ 4538.892242] CPU: 1 PID: 2064 Comm: clamd Not tainted 3.10.1.0-1-linaro-omap #1ubuntu1~ci+130723003933-Ubuntu [ 4538.892242] task: edb09500 ti: ec91e000 task.ti: ec91e000 [ 4538.892272] PC is at 0xb6e2f0d4 [ 4538.892272] LR is at 0xb6eeec01 [ 4538.892272] pc : [<b6e2f0d4>] lr : [<b6eeec01>] psr: 000f0130 [ 4538.892272] sp : be8b472c ip : 62323337 fp : 0000684a [ 4538.892303] r10: 0084d750 r9 : 00000200 r8 : e86d6a2f [ 4538.892303] r7 : 0a0a0a0a r6 : 69393e32 r5 : 0080bf24 r4 : 0080bf28 [ 4538.892333] r3 : 81010100 r2 : 63333438 r1 : 0000000a r0 : 0080bf24 [ 4538.892333] Flags: nzcv IRQs on FIQs on Mode USER_32 ISA Thumb Segment user [ 4538.892333] Control: 50c5387d Table: acbd404a DAC: 55555555 [ 4538.892364] [ 4538.892364] R8: 0xe86d69af: [ 4538.892364] 69ac 6a6f7254 412e6e61 746e6567 3939332d 00303934 b1aa3270 25060000 47a83ca7 [ 4538.892395] 69cc e4ebc453 91ad979e 23363f8b fd49d9d0 773b48ba ad58f7d3 04c351eb 96e4414f [ 4538.892395] 69ec 7e1a3ac7 f39072a5 e362cedb b119b3e0 b595375e b2137762 b19f99a8 b10dc638 [ 4538.892395] 6a0c 18060000 2e6e6957 6a6f7254 412e6e61 746e6567 3939332d 00303534 b23ade28 [ 4538.892395] 6a2c 18060000 2e6e6957 6a6f7254 462e6e61 61656b61 37342d76 00373131 ac58376e [ 4538.892395] 6a4c 72542e6e 6e616a6f 3434382e 35313336 3e55c600 412e6eb2 72617764 61472e65 [ 4538.892517] 6a6c 6176656d 2d65636e 34393132 55b20037 1604b173 2e6e6957 6a6f7254 462e6e61 [ 4538.892547] 6a8c 61656b61 37342d76 00343131 b652e2c0 72542e6e 6e616a6f 7075532e 756a7265 [ 4538.892547] 6aac 322d6e61 fb003731 15b23a2b 2e6e6957 6a6f7254 412e6e61 746e6567 3939332d [ 4538.892547] CPU: 1 PID: 2064 Comm: clamd Not tainted 3.10.1.0-1-linaro-omap #1ubuntu1~ci+130723003933-Ubuntu [ 4538.892547] [<c001175d>] (unwind_backtrace+0x1/0x9c) from [<c000f625>] (show_stack+0x11/0x14) [ 4538.892639] [<c000f625>] (show_stack+0x11/0x14) from [<c0010819>] (handle_IPI+0xd5/0x158) [ 4538.892669] [<c0010819>] (handle_IPI+0xd5/0x158) from [<c00084ff>] (gic_handle_irq+0x4b/0x50) [ 4538.892669] [<c00084ff>] (gic_handle_irq+0x4b/0x50) from [<c0453369>] (__irq_usr+0x49/0x60) [ 4538.892700] Exception stack(0xec91ffb0 to 0xec91fff8) [ 4538.892700] ffa0: 0080bf24 0000000a 63333438 81010100 [ 4538.892730] ffc0: 0080bf28 0080bf24 69393e32 0a0a0a0a e86d6a2f 00000200 0084d750 0000684a [ 4538.892730] ffe0: 62323337 be8b472c b6eeec01 b6e2f0d4 000f0130 ffffffff