Hi, On 01/03/2016 at 09:38:33 -0600, Josh Cartwright wrote : > On Mon, Feb 29, 2016 at 07:46:35PM -1000, Jean-Denis Girard wrote: > > Hello Josh, > > Hello, > > > Le 29/02/2016 06:18, Josh Cartwright a écrit : > > > I think your best bet will be to try to get early console output, with > > > the hope that you can get visibility into what is going wrong. I'm sure > > > there are many tutorials out there on how to build a kernel with this > > > serial debugging information. Do a search for DEBUG_LL, earlyprintk, > > > and perhaps earlycon; these are not -rt specific. > > > > Thanks for your advice. I managed to obtain earlyprintk, this is what I got: > > Great, this helps a lot. > > > Uncompressing Linux... done, booting the kernel. > > Booting Linux on physical CPU 0x0 > > Linux version 4.4.3-rt9 (jdg@xxxxxxxxxxxxxxx) (gcc version 5.2.1 > > 20151104 (Red Hat Cross 5.2.1-4) (GCC) ) #10 PREEMPT RT Mon Feb 29 > > 13:01:47 TAHT 2016 > > CPU: ARM926EJ-S [41069265] revision 5 (ARMv5TEJ), cr=0005317f > > CPU: VIVT data cache, VIVT instruction cache > > Machine model: Acme Systems Arietta G25 > [..] > > Unable to handle kernel NULL pointer dereference at virtual address 00000000 > > pgd = c0004000 > > [00000000] *pgd=00000000 > > Internal error: Oops: 5 [#1] PREEMPT ARM > > Modules linked in: > > CPU: 0 PID: 0 Comm: swapper Not tainted 4.4.3-rt9 #10 > > Hardware name: Atmel AT91SAM9 > > task: c0537dd0 ti: c0534000 task.ti: c0534000 > > PC is at try_to_wake_up+0x34/0x228 > > LR is at kthread_create_on_node+0x94/0x134 > [..] > > [<c0030dfc>] (try_to_wake_up) from [<c002d084>] > > (kthread_create_on_node+0x94/0x134) > > [<c002d084>] (kthread_create_on_node) from [<c0040668>] > > (setup_irq_thread+0x38/0xd4) > > [<c0040668>] (setup_irq_thread) from [<c0041634>] (__setup_irq+0x1a8/0x648) > > [<c0041634>] (__setup_irq) from [<c0041c3c>] > > (request_threaded_irq+0xe4/0x144) > > [<c0041c3c>] (request_threaded_irq) from [<c0520640>] > > (of_at91_pmc_setup+0xe0/0x16c) > > [<c0520640>] (of_at91_pmc_setup) from [<c05202bc>] (of_clk_init+0xf4/0x1b8) > > [<c05202bc>] (of_clk_init) from [<c050c108>] (time_init+0x20/0x2c) > > [<c050c108>] (time_init) from [<c050aafc>] (start_kernel+0x248/0x35c) > > [<c050aafc>] (start_kernel) from [<20008048>] (0x20008048) > > Code: e3c3303f e5932004 e2822001 e5832004 (e5902000) > > ---[ end trace 0000000000000001 ]--- > > This confirms that the problem you are seeing is the same problem > Alexandre and Boris solved in: > > https://www.spinics.net/lists/kernel/msg2172523.html > > It doesn't look like it's landed upstream yet (although it's been in > next since last week). > > It looks like Alexandre has pushed a tag with these changes (destined > for 4.6) at: > > git://git.kernel.org/pub/scm/linux/kernel/git/abelloni/linux.git at91-ab-4.6-drivers > > You can cherry-pick back those top 13 commits and give it a try. > > If you can confirm that those changes fix your problem, they should be > considered for cherry-picking into 4.4-rt officially. > I also have that branch for preempt-rt on at91: https://github.com/alexandrebelloni/linux/tree/at91-rt I'll make sure my changes will land in the next -rt releases but I had to make sure which version will land in the mainline first. -- Alexandre Belloni, Free Electrons Embedded Linux, Kernel and Android engineering http://free-electrons.com -- To unsubscribe from this list: send the line "unsubscribe linux-rt-users" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
