On 08/17/2018 02:25 PM, Peter Robinson wrote: > On Thu, Aug 16, 2018 at 11:58 PM, Russell King - ARM Linux > <li...@armlinux.org.uk> wrote: >> On Thu, Aug 16, 2018 at 10:35:16PM +0200, Marc Haber wrote: >>> On Mon, Jun 25, 2018 at 05:41:27PM +0100, Peter Robinson wrote: >>>> So with that and the other fix there was no improvement, with those >>>> and the BPF JIT disabled it works, I'm not sure if the two patches >>>> have any effect with the JIT disabled though. >>> >>> I can confirm the crash with the released 4.18.1 on Banana Pi, and I can >>> also confirm that disabling BPF JIT makes the Banana Pi work again., >> >> I'm afraid that the information in the crash dumps is insufficient >> to be able to work very much out about these crashes. >> >> We need a recipe (kernel configuration and what userspace is doing) >> so that it's possible to recreate the crash, or we need responses >> to requests for information - I requested the disassembly of >> sk_filter_trim_cap and the BPF code dump via setting a sysctl back >> in early July. Without this, as I say, I don't see how this problem >> can be progressed. > > I can provide a kernel config [1] but I've not had enough time to sit > down and get the rest of the stuff and debug it due to a combination > of travel and other priorities.
Did you get a chance to try latest kernel from Linus' tree [1] from last few days to see whether the issue is still persistent? There have been a number of improvements, bit strange why e.g. Russell didn't run into it while others have, hmm. Perhaps due to EABI vs non EABI. [1] git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git >> If the problem is at boot, one way to set the sysctl would be to >> hack the kernel and explicitly initialise the sysctl to '2', or >> boot with init=/bin/sh, then manually mount /proc, set the sysctl, >> and then "exec /sbin/init" from that shell. (Remember there's no >> job control in that shell, so ^z, ^c, etc do not work.) > > It starts to happen in the early kernel boot long before we get to any > userspace across a number of ARMv7 devices (RPi2/3, BeagleBone and > AllWinner H3 based devices at least). > > [1] https://pbrobinson.fedorapeople.org/kernel-armv7hl.config I'd have one potential bug suspicion, for the 4.18 one you were trying, could you run with the below patch to see whether it would help? Thanks, Daniel diff --git a/arch/arm/net/bpf_jit_32.c b/arch/arm/net/bpf_jit_32.c index f6a62ae..c864f6b 100644 --- a/arch/arm/net/bpf_jit_32.c +++ b/arch/arm/net/bpf_jit_32.c @@ -238,7 +238,7 @@ static void jit_fill_hole(void *area, unsigned int size) #define STACK_SIZE ALIGN(_STACK_SIZE, STACK_ALIGNMENT) /* Get the offset of eBPF REGISTERs stored on scratch space. */ -#define STACK_VAR(off) (STACK_SIZE - off) +#define STACK_VAR(off) (STACK_SIZE - off - 4) #if __LINUX_ARM_ARCH__ < 7
