Rahul Rameshbabu <rrameshb...@nvidia.com> writes: > On Fri, 15 Dec, 2023 23:44:49 +1100 Michael Ellerman <m...@ellerman.id.au> > wrote: >> There are reports of kernels crashing due to stack overflow while >> running OpenShift (Kubernetes). The primary contributor to the stack >> usage seems to be openvswitch, which is used by OVN-Kubernetes (based on >> OVN (Open Virtual Network)), but NFS also contributes in some stack >> traces. >> >> There may be some opportunities to reduce stack usage in the openvswitch >> code, but doing so potentially require tradeoffs vs performance, and >> also requires testing across architectures. >> >> Looking at stack usage across the kernel (using -fstack-usage), shows >> that ppc64le stack frames are on average 50-100% larger than the >> equivalent function built for x86-64. Which is not surprising given the >> minimum stack frame size is 32 bytes on ppc64le vs 16 bytes on x86-64. >> >> So increase the default stack size to 32KB for the modern 64-bit Book3S >> platforms, ie. pseries (virtualised) and powernv (bare metal). That >> leaves the older systems like G5s, and the AmigaOne (pasemi) with a 16KB >> stack which should be sufficient on those machines. >> >> Signed-off-by: Michael Ellerman <m...@ellerman.id.au> >> --- > > We noticed this change is causing assembler issues for us when building > the kernel. > > make ARCH=powerpc > KERNELRELEASE=6.8.0-rc2_for_upstream_debug_2024_02_06_20_01 > KBUILD_BUILD_VERSION=1 > arch/powerpc/kernel/switch.S: Assembler messages: > arch/powerpc/kernel/switch.S:249: Error: operand out of range > (0x000000000000fe50 is not between 0xffffffffffff8000 and 0x0000000000007fff) > make[6]: *** [scripts/Makefile.build:361: arch/powerpc/kernel/switch.o] > Error 1 > make[5]: *** [scripts/Makefile.build:481: arch/powerpc/kernel] Error 2 > make[5]: *** Waiting for unfinished jobs.... > make[4]: *** [scripts/Makefile.build:481: arch/powerpc] Error 2 > make[4]: *** Waiting for unfinished jobs.... > make[3]: *** [Makefile:1921: .] Error 2
There's a fix in my fixes branch: https://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux.git/commit/?h=fixes&id=f1acb109505d983779bbb7e20a1ee6244d2b5736 I'll send it to Linus this week. cheers
