On 03.01.22 08:29, C Smith wrote: > I have been getting kernel Oopses with x86 Xenomai 3.1 (and 3.2.1). > In numerous tests, I can't keep a computer running for more than a day > before the computer hard-locks (no kbd/mouse/ping). Frequently the > kernel Oopses within 4-6 hours. I have tried 2 identical motherboards, > changed RAM, and tried another manufacturer's motherboard on a 3rd > computer. > > * Can someone supply me with a known successful x68 kernel 4.19.89 > config so I can compare and try those settings? I will attach my > kernel config to this email, in hopes someone can see something wrong > with them. > > Specs: Intel i5-4590 CPU, Advantech motherboard with Q87 intel > chipset, 8G RAM, Moxa 4-port PCI card w/ 16750 UARTs, 2 motherboard > 16550 UARTS (in ISA memory range), Peak PCI CAN card, Xenomai 3.1 > (also xeno 3.2.1), Distro: RHEL8, with xenomai ipipe-patched 4.19.89 > kernel from kernel.org source. > > Sometimes onscreen (in a text terminal) I get this Oops: > > kernel tried to execute NX-protected page - exploit attempt? (uid: 1000) > BUG: unable to handle kernel paging request at ... > PGD ... P4D ... PUD .. PHD ... > Oops: 0011 [#1] SMP PTI > CPU: 1 P1D: 3539 Comm: gui Tainted: G OE 4.19.89xeno3.1-i64x3832 #2 > Hardware name: To be filled by O.E.M. To be filled by O.E.M./SHARKBAY, > BIOS 4.6.5 08/29/2017 > I-pipe domain: Linux > RIP: ... : ... > Code: Bad RIP value. > > Which means the Instruction Pointer is in a Data area. That is bad, > and I think it is caused by Cobalt code not restoring the > stack/registers correctly during a context switch. > Other times I get : > > Kernel Panic - not syncing: stack-protector: Kernel stack is corrupted > in: __xnsched_run.part.63 h - > CPU: 1 PID: 2409 Comm: appnrtB Tainted: G OE 4.19.89Nen03.1-i64x8632 #2 > Hardware name: To be filled by 0.E.M. To be filled by OEM, BIOS 4.6.5 > 04/23/2021 > I-pipe domain: Linux > Call Trace: > <IRQ> > dump_stack+8x95/8xna > panic+8xe§l8x246 > ? ___xnsched_run.part.63+8x5c4/8x4d0 > __stack_chhk_fail+8x19x8x28 > ___xnsched_run.part.63+8x§c4/Bx§d8 > ? release_ioapic_irq+8x3f/8x58 > ? __ipipe_end_fasteoi_irq+BNZZ/8x38 > xnintr;edge_vec_handler+BXBIA/8x558 > __ipipe_do_sync_pipeline+8xS/ana > dispatch_irq_head+8xe6/Bx118 > __ipipe_dispatch_irq+ax1bc/Bx1e8 > __ipipe_handle_irq+8x198/x208 > ? common_interrupt+8xf/Bx2c > </IRQ> > > The accompanying stack trace seems to implicate an ipipe interrupt > handler as causing the problem. I'm using xeno_16550A.ko interrupts on > an isolated interrupt level (IRQ 18). > > Interestingly, the Cobalt scheduler and my RT userspace app are still > running after this, even though the Linux kernel is halted. I proved > this on an oscilloscope: I can see serial packets going into and out > of the serial ports at the expected periodic time base. > > (Note that the text of these kernel faults above is reconstructed with > OCR so some addresses are not complete. The computer is hard-locked in > a text terminal when these happen. I can supply the full JPG pictures > or re-type addresses if you like.) > > The application scenario which causes the above problems: The primary > app, “apprt2”, is a 32-bit userspace app (compiled -m32) running on > CPU core 1 (by fixed affinity), on 64 bit Xenomai 3.1 with ipipe patch > applied for x86 kernel 4.19.89. It has shared memory via mmap() with > an RTDM module (“modrt1”) but nothing is happening in “modrt1” at > present, no interrupts etc. There are also two non-RT userspace linux > apps which have attached to the same shared memory via mmap() but > those are doing nothing much during these tests. I have attached > several (1-6) RS232 serial devices and one CAN device all > communicating with “apprt2”. > > The system does not fault (for 48+ hours) when no peripheral > connections are present (Serial/CAN). The faults happen with Serial > traffic, whether the CAN device is attached or not. The CAN device > alone with no Serial does not cause the fault (tested for 48+ hours), > and the fault has also happened when the motherboard serial ports were > used, so the PCI Moxa code is not implicated. > > Note that in order to get 32-bit userspace support to fully work I had > to manually patch the 16550A.c serial driver with the 32 bit > “compatibility” patch from the xenomai mailing list. That works OK and > my apps can communicate fine for hours. The serial packets in my > applications have CRC checks so we know if data ever gets corrupted. > > Note that my apps have been running OK 32-bit on Xenomai v2.6 for two > years. Also I ran my apps compiled as 64 bit on Xenomai v3.0.12 and > did not get any faults in a test lasting 21+ hours (serial driver > only, no CAN). > > Since I imagine Xenomai developers prefer to debug on recent builds, I > also tested this on Xenomai 3.2.1 and I recompiled my apps 64 bit. I > still get kernel Oopses with Xeno 3.2.1 : > > kernel tried to execute NX-protected page - exploit attempt? (uid: 1000) > BUG: unable to handle kernel paging request at ... > PGD ... P4D ... PUD ... PMD ... > Oops: 0011 [#1] SMP PTI > CPU: 1 P1D: 3539 Comm: appnrtA Tainted: G OE 4.19.89xeno3.1-i64x3832 #2 > Hardware name: To be filled by O.E.M. To be filled by O.E.M./SHARKBAY, > BIOS 4.6.5 08/29/2017 > I-pipe domain: Linux > RIP: … : ... > Code: Bad RIP value. > … > > * Is there some way to instrument the Cobalt kernel to debug this ? It > seems impossible to get any debug data from /proc/xenomai because the > Linux kernel is Oopsed. > > A debugging problem: occasionally with my apps compiled 64 bit on > Xeno 3.1 or 3.2 the tests run 24+ hours OK (but would fault > eventually, or in another test). So I get 'false positives' and it > takes weeks to make progress. It is easiest to generate a kernel Oops > rapidly on Xeno 3.1 with my apps compiled 32 bit. So to expedite the > testing process may I propose to keep compiling 32 bit and we > instrument Xeno-3.1 (k4.19.89), and ultimately port the fix to > xeno-3.2 (k4.19.89)? > > Thanks. -C Smith
The issue is only with 4.19-ipipe kernels? Are you able to test also with 5.4-ipipe or 5.10/15-dovetail? Can you also spend an extra UART for a kernel console so that crash dumps may have a better chance to be reported? Regarding reference configurations: See also https://source.denx.de/Xenomai/xenomai-images/-/tree/master/recipes-kernel/linux/files. Not optimal ones, but tested. Jan -- Siemens AG, T RDA IOT Corporate Competence Center Embedded Linux
