From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: Pawan Gupta <pawan.kumar.gupta@linux.intel.com>
Cc: stable@vger.kernel.org, Sasha Levin <sashal@kernel.org>,
bpf@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
loongarch@lists.linux.dev, linuxppc-dev@lists.ozlabs.org,
linux-riscv@lists.infradead.org, x86@kernel.org,
Alexei Starovoitov <ast@kernel.org>,
Daniel Borkmann <daniel@iogearbox.net>,
Dave Hansen <dave.hansen@linux.intel.com>
Subject: Re: [PATCH 6.16.y 0/6] cBPF JIT spray hardening
Date: Tue, 21 Jul 2026 15:08:11 +0200 [thread overview]
Message-ID: <2026072151-outsell-suburb-64ea@gregkh> (raw)
In-Reply-To: <20260714-cbpf-jit-spray-hardening-6-16-y-v1-0-2fc3e16263ac@linux.intel.com>
On Tue, Jul 14, 2026 at 11:58:24AM -0700, Pawan Gupta wrote:
> Hi,
>
> These backports harden BPF JIT against spectre-v2 class of attacks. Without
> a predictor flush, execution of new BPF program may use stale prediction
> left behind by the freed one.
>
> To avoid this, issue an IBPB flush on all CPUs on JIT program allocation.
> The flush is conditional to spectre-v2 mitigation applied.
>
> Patch 1-2: Adds the predictor flush hook and enables it on x86 via IBPB.
>
> bpf: Support for hardening against JIT spraying
> x86/bugs: Enable IBPB flush on BPF JIT allocation
>
> Patch 3-6: Narrow the flush to only unprivileged JIT allocations
> to avoid redundant flushes. Also adds pack-selection changes
> that minimizes flushes.
>
> bpf: Restrict JIT predictor flush to cBPF
> bpf: Skip redundant IBPB in pack allocator
> bpf: Prefer packs that won't trigger an IBPB flush on allocation
> bpf: Prefer dirty packs for eBPF allocations
>
> This one is mostly similar to 6.18:
>
> https://lore.kernel.org/all/20260713-cbpf-jit-spray-hardening-6-18-y-v1-0-755f60c55705@linux.intel.com/
There is no active 6.16.y kernel branch, so why is this being sent to
us?
confused,
greg k-h
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WARNING: multiple messages have this Message-ID (diff)
From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: Pawan Gupta <pawan.kumar.gupta@linux.intel.com>
Cc: stable@vger.kernel.org, Sasha Levin <sashal@kernel.org>,
bpf@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
loongarch@lists.linux.dev, linuxppc-dev@lists.ozlabs.org,
linux-riscv@lists.infradead.org, x86@kernel.org,
Alexei Starovoitov <ast@kernel.org>,
Daniel Borkmann <daniel@iogearbox.net>,
Dave Hansen <dave.hansen@linux.intel.com>
Subject: Re: [PATCH 6.16.y 0/6] cBPF JIT spray hardening
Date: Tue, 21 Jul 2026 15:08:11 +0200 [thread overview]
Message-ID: <2026072151-outsell-suburb-64ea@gregkh> (raw)
In-Reply-To: <20260714-cbpf-jit-spray-hardening-6-16-y-v1-0-2fc3e16263ac@linux.intel.com>
On Tue, Jul 14, 2026 at 11:58:24AM -0700, Pawan Gupta wrote:
> Hi,
>
> These backports harden BPF JIT against spectre-v2 class of attacks. Without
> a predictor flush, execution of new BPF program may use stale prediction
> left behind by the freed one.
>
> To avoid this, issue an IBPB flush on all CPUs on JIT program allocation.
> The flush is conditional to spectre-v2 mitigation applied.
>
> Patch 1-2: Adds the predictor flush hook and enables it on x86 via IBPB.
>
> bpf: Support for hardening against JIT spraying
> x86/bugs: Enable IBPB flush on BPF JIT allocation
>
> Patch 3-6: Narrow the flush to only unprivileged JIT allocations
> to avoid redundant flushes. Also adds pack-selection changes
> that minimizes flushes.
>
> bpf: Restrict JIT predictor flush to cBPF
> bpf: Skip redundant IBPB in pack allocator
> bpf: Prefer packs that won't trigger an IBPB flush on allocation
> bpf: Prefer dirty packs for eBPF allocations
>
> This one is mostly similar to 6.18:
>
> https://lore.kernel.org/all/20260713-cbpf-jit-spray-hardening-6-18-y-v1-0-755f60c55705@linux.intel.com/
There is no active 6.16.y kernel branch, so why is this being sent to
us?
confused,
greg k-h
next prev parent reply other threads:[~2026-07-21 13:08 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-07-14 18:58 [PATCH 6.16.y 0/6] cBPF JIT spray hardening Pawan Gupta
2026-07-14 18:58 ` Pawan Gupta
2026-07-14 18:58 ` [PATCH 6.16.y 1/6] bpf: Support for hardening against JIT spraying Pawan Gupta
2026-07-14 18:58 ` Pawan Gupta
2026-07-14 19:17 ` sashiko-bot
2026-07-14 18:58 ` [PATCH 6.16.y 2/6] x86/bugs: Enable IBPB flush on BPF JIT allocation Pawan Gupta
2026-07-14 18:58 ` Pawan Gupta
2026-07-14 19:36 ` sashiko-bot
2026-07-14 18:59 ` [PATCH 6.16.y 3/6] bpf: Restrict JIT predictor flush to cBPF Pawan Gupta
2026-07-14 18:59 ` Pawan Gupta
2026-07-14 19:28 ` sashiko-bot
2026-07-14 18:59 ` [PATCH 6.16.y 4/6] bpf: Skip redundant IBPB in pack allocator Pawan Gupta
2026-07-14 18:59 ` Pawan Gupta
2026-07-14 18:59 ` [PATCH 6.16.y 5/6] bpf: Prefer packs that won't trigger an IBPB flush on allocation Pawan Gupta
2026-07-14 18:59 ` Pawan Gupta
2026-07-14 18:59 ` [PATCH 6.16.y 6/6] bpf: Prefer dirty packs for eBPF allocations Pawan Gupta
2026-07-14 18:59 ` Pawan Gupta
2026-07-21 13:08 ` Greg Kroah-Hartman [this message]
2026-07-21 13:08 ` [PATCH 6.16.y 0/6] cBPF JIT spray hardening Greg Kroah-Hartman
2026-07-22 15:18 ` Pawan Gupta
2026-07-22 15:18 ` Pawan Gupta
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