From: sashiko-bot@kernel.org
To: "Matt Turner" <mattst88@gmail.com>
Cc: linux-perf-users@vger.kernel.org
Subject: Re: [PATCH 1/4] alpha: fix stale user_stack_pointer()
Date: Sun, 11 Oct 2026 20:32:47 +0000 [thread overview]
Message-ID: <sashiko-outbox-167454@kernel.org> (raw)
In-Reply-To: <20261011-alpha-perf-regs-v3-v1-1-eaa625a39712@gmail.com>
> PALcode keeps the user stack pointer in the PCB, not the trap frame, so
> pt_regs->usp is only valid where entry code stores it: entSys,
> do_entArith() and do_entIF(). Interrupts, page faults and unaligned
> traps leave it stale, and ptrace and /proc/<pid>/syscall read it
> through user_stack_pointer().
>
> A user-mode pt_regs is at the top of its task's stack, so find the
> thread_info from it and use rdusp() for current or pcb.usp otherwise,
> as KSTK_ESP() and the regset code already do.
>
> Fixes: 8a2857bc2b30 ("alpha: enable regset-based ptrace and core dumps")
> Assisted-by: Claude:claude-opus-5-5
> Signed-off-by: Matt Turner <mattst88@gmail.com>
Sashiko has reviewed this patch and found no issues. It looks great!
--
Sashiko AI review · https://sashiko.dev/#/patchset/20261011-alpha-perf-regs-v3-v1-0-eaa625a39712@gmail.com?part=1
next prev parent reply other threads:[~2026-10-11 20:32 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-10-11 20:16 [PATCH 0/4] alpha: perf register sampling and user stack dumps Matt Turner
2026-10-11 20:16 ` [PATCH 1/4] alpha: fix stale user_stack_pointer() Matt Turner
2026-10-11 20:32 ` sashiko-bot [this message]
2026-10-12 16:18 ` Magnus Lindholm
2026-10-11 20:16 ` [PATCH 2/4] alpha: stop storing the user stack pointer in pt_regs Matt Turner
2026-10-11 20:30 ` sashiko-bot
2026-10-12 16:20 ` Magnus Lindholm
2026-10-11 20:16 ` [PATCH 3/4] alpha: use user_stack_pointer() in KSTK_ESP() and dump_elf_thread() Matt Turner
2026-10-11 20:31 ` sashiko-bot
2026-10-12 17:12 ` Magnus Lindholm
2026-10-11 20:16 ` [PATCH 4/4] alpha: add HAVE_PERF_REGS and HAVE_PERF_USER_STACK_DUMP support Matt Turner
2026-10-11 20:25 ` sashiko-bot
2026-10-12 17:34 ` Magnus Lindholm
2026-10-11 21:47 ` [PATCH 0/4] alpha: perf register sampling and user stack dumps Ian Rogers
2026-10-12 15:51 ` Magnus Lindholm
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