From: Thomas Gleixner <tglx@kernel.org>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Mathias Stearn <mathias@mongodb.com>,
Dmitry Vyukov <dvyukov@google.com>,
Jinjie Ruan <ruanjinjie@huawei.com>,
linux-man@vger.kernel.org, Mark Rutland <mark.rutland@arm.com>,
Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
Catalin Marinas <catalin.marinas@arm.com>,
Will Deacon <will@kernel.org>, Boqun Feng <boqun.feng@gmail.com>,
"Paul E. McKenney" <paulmck@kernel.org>,
Chris Kennelly <ckennelly@google.com>,
regressions@lists.linux.dev, linux-kernel@vger.kernel.org,
linux-arm-kernel@lists.infradead.org,
Ingo Molnar <mingo@kernel.org>,
Blake Oler <blake.oler@mongodb.com>,
Florian Weimer <fweimer@redhat.com>,
Rich Felker <dalias@libc.org>,
Matthew Wilcox <willy@infradead.org>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Linus Torvalds <torvalds@linuxfoundation.org>
Subject: Re: [REGRESSION] rseq: refactoring in v6.19 broke everyone on arm64 and tcmalloc everywhere
Date: Tue, 28 Apr 2026 10:51:29 +0200 [thread overview]
Message-ID: <87zf2nxyb2.ffs@tglx> (raw)
In-Reply-To: <20260428073938.GH3126523@noisy.programming.kicks-ass.net>
On Tue, Apr 28 2026 at 09:39, Peter Zijlstra wrote:
> On Mon, Apr 27, 2026 at 12:04:48AM +0200, Thomas Gleixner wrote:
>> static inline void rseq_signal_deliver(struct ksignal *ksig, struct pt_regs *regs)
>> {
>> - if (IS_ENABLED(CONFIG_GENERIC_IRQ_ENTRY)) {
>> + if (IS_ENABLED(CONFIG_GENERIC_IRQ_ENTRY) && rseq_optimized(current)) {
>
> rseq_optimized() already implies GENERIC_IRQ_ENTRY
Indeed.
>> + u8 optimized;
>> union {
>> u16 error;
>> struct {
>
> I know you like the 'optimized' name, it is faster etc. However, the
> description there suggests: has_rseq_v2 not be a bad name.
>
> And while I write this, I figured we could have the value of has_rseq be
> 2, rather than 1, but this might end up generating worse code, dunno,
> haven't tried yet.
Tried that early on and it was worse, but back the approach has changed
since then and I just validated that it's actually fine to do so. Fixed.
Thanks,
tglx
next prev parent reply other threads:[~2026-04-28 8:51 UTC|newest]
Thread overview: 57+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-04-22 9:50 [REGRESSION] rseq: refactoring in v6.19 broke everyone on arm64 and tcmalloc everywhere Mathias Stearn
2026-04-22 12:56 ` Peter Zijlstra
2026-04-22 13:13 ` Peter Zijlstra
2026-04-23 10:38 ` Mathias Stearn
[not found] ` <CAHnCjA2fa+dP1+yCYNQrTXQaW-JdtfMj7wMikwMeeCRg-3NhiA@mail.gmail.com>
2026-04-23 11:48 ` Thomas Gleixner
2026-04-23 12:11 ` Mathias Stearn
2026-04-23 17:19 ` Thomas Gleixner
2026-04-23 17:38 ` Chris Kennelly
2026-04-23 17:47 ` Mathieu Desnoyers
2026-04-23 19:39 ` Thomas Gleixner
2026-04-23 17:41 ` Linus Torvalds
2026-04-23 18:35 ` Mathias Stearn
2026-04-23 18:53 ` Mark Rutland
2026-04-23 21:03 ` Thomas Gleixner
2026-04-23 21:28 ` Linus Torvalds
2026-04-23 23:08 ` Linus Torvalds
2026-04-27 7:06 ` Florian Weimer
2026-04-27 16:12 ` Linus Torvalds
2026-04-22 13:09 ` Mark Rutland
2026-04-22 17:49 ` Thomas Gleixner
2026-04-22 18:11 ` Mark Rutland
2026-04-22 19:47 ` Thomas Gleixner
2026-04-23 1:48 ` Jinjie Ruan
2026-04-23 5:53 ` Dmitry Vyukov
2026-04-23 10:39 ` Thomas Gleixner
2026-04-23 10:51 ` Mathias Stearn
2026-04-23 12:24 ` David Laight
2026-04-23 19:31 ` Thomas Gleixner
2026-04-24 7:56 ` Dmitry Vyukov
2026-04-24 8:32 ` Mathias Stearn
2026-04-24 9:30 ` Dmitry Vyukov
2026-04-24 14:16 ` Thomas Gleixner
2026-04-24 15:03 ` Peter Zijlstra
2026-04-24 19:44 ` Thomas Gleixner
2026-04-26 22:04 ` Thomas Gleixner
2026-04-27 7:40 ` Florian Weimer
2026-04-27 11:03 ` Thomas Gleixner
2026-04-27 18:35 ` Mathieu Desnoyers
2026-04-27 21:06 ` Thomas Gleixner
2026-04-28 6:11 ` Dmitry Vyukov
2026-04-28 8:07 ` Thomas Gleixner
2026-04-28 8:18 ` Thomas Gleixner
[not found] ` <CACT4Y+b_RH2eZMuh1YUyqnoK-5KUpdWW4z1q2ZQWkY_GcBqmNw@mail.gmail.com>
2026-04-28 13:31 ` Mathias Stearn
2026-04-28 7:39 ` Peter Zijlstra
2026-04-28 8:13 ` Peter Zijlstra
2026-04-28 8:51 ` Thomas Gleixner [this message]
2026-04-28 8:03 ` Peter Zijlstra
2026-04-28 8:36 ` Thomas Gleixner
2026-04-23 12:11 ` Alejandro Colomar
2026-04-23 12:54 ` Mathieu Desnoyers
2026-04-23 12:29 ` Mathieu Desnoyers
2026-04-23 12:36 ` Dmitry Vyukov
2026-04-23 12:53 ` Mathieu Desnoyers
2026-04-23 12:58 ` Dmitry Vyukov
2026-04-24 16:45 ` [PATCH] arm64/entry: Fix arm64-specific rseq brokenness (was: Re: [REGRESSION] rseq: refactoring in v6.19 broke everyone on arm64) " Mark Rutland
2026-04-28 1:39 ` [PATCH] arm64/entry: Fix arm64-specific rseq brokenness Jinjie Ruan
2026-04-28 13:40 ` Mark Rutland
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