Hi Matt and Magnus, On Mon, Oct 12, 2026 at 2:40 PM Matt Turner <[email protected]> wrote: > > This series lets elfutils unwind on alpha, from core files > (eu-stack --core), from stopped threads (eu-stack -p) and from perf > samples (eu-stackprof). > > Patch 1 fixes the prstatus layout, which had pc and unique one slot too > far. Patch 2 adds the ABI CFI and patch 3 reads the registers of a > stopped thread with ptrace. Patch 4 unwinds from perf samples. > > Since Linux 7.1 the kernel returns a peeked value in [-4095, -1] as an > error, which breaks patch 3 for threads with such a register value (seen > with run-backtrace-native.sh). "alpha: enable GENERIC_ENTRY", queued in > the alpha tree, fixes that. > > Patch 4 depends on the proposed kernel support for perf register > sampling on alpha, which also provides <asm/perf_regs.h>: > > https://lore.kernel.org/r/[email protected] > > Patch 2 is also what perf record --call-graph dwarf needs from libdw on > alpha. The perf tool side is posted as: > > https://lore.kernel.org/r/[email protected] > > Signed-off-by: Matt Turner <[email protected]>
Thanks for the patches, they have been merged. On Mon, Oct 12, 2026 at 5:48 PM Magnus Lindholm <[email protected]> wrote: > I built the full series and tested it with your kernel and perf-tools > patches on my AlphaServer ES40 (EV67). > > Using the patched libdw/libelf, perf recovered the expected DWARF > caller chains from both existing and fresh recordings. Frames whose > CFA depends on r15 stopped at the sampled frame, as documented. > > This testing covers perf's libdw unwinding path only. > > Tested-by: Magnus Lindholm <[email protected]> Thank you for testing this. Aaron
