From: Peter Zijlstra <peterz@infradead.org>
To: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Cc: bpf@vger.kernel.org, linux-kernel@vger.kernel.org,
Linus Torvalds <torvalds@linux-foundation.org>,
Will Deacon <will@kernel.org>, Waiman Long <llong@redhat.com>,
Alexei Starovoitov <ast@kernel.org>,
Andrii Nakryiko <andrii@kernel.org>,
Daniel Borkmann <daniel@iogearbox.net>,
Martin KaFai Lau <martin.lau@kernel.org>,
Eduard Zingerman <eddyz87@gmail.com>,
"Paul E. McKenney" <paulmck@kernel.org>,
Tejun Heo <tj@kernel.org>, Barret Rhoden <brho@google.com>,
Josh Don <joshdon@google.com>, Dohyun Kim <dohyunkim@google.com>,
linux-arm-kernel@lists.infradead.org, kernel-team@meta.com
Subject: Re: [PATCH bpf-next v2 00/26] Resilient Queued Spin Lock
Date: Mon, 10 Feb 2025 10:31:27 +0100 [thread overview]
Message-ID: <20250210093127.GD10324@noisy.programming.kicks-ass.net> (raw)
In-Reply-To: <20250206105435.2159977-1-memxor@gmail.com>
On Thu, Feb 06, 2025 at 02:54:08AM -0800, Kumar Kartikeya Dwivedi wrote:
> Additionally, eBPF programs attached to different parts of the kernel
> can introduce new control flow into the kernel, which increases the
> likelihood of deadlocks in code not written to handle reentrancy. There
> have been multiple syzbot reports surfacing deadlocks in internal kernel
> code due to the diverse ways in which eBPF programs can be attached to
> different parts of the kernel. By switching the BPF subsystem’s lock
> usage to rqspinlock, all of these issues can be mitigated at runtime.
Only if the called stuff is using this new lock. IIRC we've had a number
of cases where eBPF was used to tie together 'normal' kernel functions
in a way that wasn't sound. You can't help there.
As an example, eBPF calling strncpy_from_user(), which ends up in fault
injection and badness happens -- this has been since fixed, but still.
next prev parent reply other threads:[~2025-02-10 9:31 UTC|newest]
Thread overview: 67+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-02-06 10:54 [PATCH bpf-next v2 00/26] Resilient Queued Spin Lock Kumar Kartikeya Dwivedi
2025-02-06 10:54 ` [PATCH bpf-next v2 01/26] locking: Move MCS struct definition to public header Kumar Kartikeya Dwivedi
2025-02-06 10:54 ` [PATCH bpf-next v2 02/26] locking: Move common qspinlock helpers to a private header Kumar Kartikeya Dwivedi
2025-02-07 23:21 ` kernel test robot
2025-02-06 10:54 ` [PATCH bpf-next v2 03/26] locking: Allow obtaining result of arch_mcs_spin_lock_contended Kumar Kartikeya Dwivedi
2025-02-06 10:54 ` [PATCH bpf-next v2 04/26] locking: Copy out qspinlock.c to rqspinlock.c Kumar Kartikeya Dwivedi
2025-02-06 10:54 ` [PATCH bpf-next v2 05/26] rqspinlock: Add rqspinlock.h header Kumar Kartikeya Dwivedi
2025-02-06 10:54 ` [PATCH bpf-next v2 06/26] rqspinlock: Drop PV and virtualization support Kumar Kartikeya Dwivedi
2025-02-06 10:54 ` [PATCH bpf-next v2 07/26] rqspinlock: Add support for timeouts Kumar Kartikeya Dwivedi
2025-02-10 9:56 ` Peter Zijlstra
2025-02-11 4:55 ` Alexei Starovoitov
2025-02-11 10:11 ` Peter Zijlstra
2025-02-11 18:00 ` Alexei Starovoitov
2025-02-06 10:54 ` [PATCH bpf-next v2 08/26] rqspinlock: Protect pending bit owners from stalls Kumar Kartikeya Dwivedi
2025-02-06 10:54 ` [PATCH bpf-next v2 09/26] rqspinlock: Protect waiters in queue " Kumar Kartikeya Dwivedi
2025-02-10 10:17 ` Peter Zijlstra
2025-02-13 6:20 ` Kumar Kartikeya Dwivedi
2025-02-06 10:54 ` [PATCH bpf-next v2 10/26] rqspinlock: Protect waiters in trylock fallback " Kumar Kartikeya Dwivedi
2025-02-06 10:54 ` [PATCH bpf-next v2 11/26] rqspinlock: Add deadlock detection and recovery Kumar Kartikeya Dwivedi
2025-02-08 1:53 ` Alexei Starovoitov
2025-02-08 3:03 ` Kumar Kartikeya Dwivedi
2025-02-10 10:21 ` Peter Zijlstra
2025-02-13 6:11 ` Kumar Kartikeya Dwivedi
2025-02-10 10:36 ` Peter Zijlstra
2025-02-06 10:54 ` [PATCH bpf-next v2 12/26] rqspinlock: Add a test-and-set fallback Kumar Kartikeya Dwivedi
2025-02-06 10:54 ` [PATCH bpf-next v2 13/26] rqspinlock: Add basic support for CONFIG_PARAVIRT Kumar Kartikeya Dwivedi
2025-02-06 10:54 ` [PATCH bpf-next v2 14/26] rqspinlock: Add helper to print a splat on timeout or deadlock Kumar Kartikeya Dwivedi
2025-02-06 10:54 ` [PATCH bpf-next v2 15/26] rqspinlock: Add macros for rqspinlock usage Kumar Kartikeya Dwivedi
2025-02-06 10:54 ` [PATCH bpf-next v2 16/26] rqspinlock: Add locktorture support Kumar Kartikeya Dwivedi
2025-02-06 10:54 ` [PATCH bpf-next v2 17/26] rqspinlock: Hardcode cond_acquire loops to asm-generic implementation Kumar Kartikeya Dwivedi
2025-02-08 1:58 ` Alexei Starovoitov
2025-02-08 3:04 ` Kumar Kartikeya Dwivedi
2025-02-10 9:53 ` Peter Zijlstra
2025-02-10 10:03 ` Peter Zijlstra
2025-02-13 6:15 ` Kumar Kartikeya Dwivedi
2025-02-06 10:54 ` [PATCH bpf-next v2 18/26] rqspinlock: Add entry to Makefile, MAINTAINERS Kumar Kartikeya Dwivedi
2025-02-07 14:14 ` kernel test robot
2025-02-07 14:45 ` kernel test robot
2025-02-08 0:43 ` kernel test robot
2025-02-06 10:54 ` [PATCH bpf-next v2 19/26] bpf: Convert hashtab.c to rqspinlock Kumar Kartikeya Dwivedi
2025-02-08 2:01 ` Alexei Starovoitov
2025-02-08 3:06 ` Kumar Kartikeya Dwivedi
2025-02-06 10:54 ` [PATCH bpf-next v2 20/26] bpf: Convert percpu_freelist.c " Kumar Kartikeya Dwivedi
2025-02-06 10:54 ` [PATCH bpf-next v2 21/26] bpf: Convert lpm_trie.c " Kumar Kartikeya Dwivedi
2025-02-06 10:54 ` [PATCH bpf-next v2 22/26] bpf: Introduce rqspinlock kfuncs Kumar Kartikeya Dwivedi
2025-02-07 13:43 ` kernel test robot
2025-02-06 10:54 ` [PATCH bpf-next v2 23/26] bpf: Handle allocation failure in acquire_lock_state Kumar Kartikeya Dwivedi
2025-02-08 2:04 ` Alexei Starovoitov
2025-02-06 10:54 ` [PATCH bpf-next v2 24/26] bpf: Implement verifier support for rqspinlock Kumar Kartikeya Dwivedi
2025-02-12 0:08 ` Eduard Zingerman
2025-02-13 6:41 ` Kumar Kartikeya Dwivedi
2025-02-06 10:54 ` [PATCH bpf-next v2 25/26] bpf: Maintain FIFO property for rqspinlock unlock Kumar Kartikeya Dwivedi
2025-02-06 10:54 ` [PATCH bpf-next v2 26/26] selftests/bpf: Add tests for rqspinlock Kumar Kartikeya Dwivedi
2025-02-12 0:14 ` Eduard Zingerman
2025-02-13 6:25 ` Kumar Kartikeya Dwivedi
2025-02-10 9:31 ` Peter Zijlstra [this message]
2025-02-10 9:38 ` [PATCH bpf-next v2 00/26] Resilient Queued Spin Lock Peter Zijlstra
2025-02-10 10:49 ` Peter Zijlstra
2025-02-11 4:37 ` Alexei Starovoitov
2025-02-11 10:43 ` Peter Zijlstra
2025-02-11 18:33 ` Alexei Starovoitov
2025-02-13 9:59 ` Peter Zijlstra
2025-02-14 2:37 ` Alexei Starovoitov
2025-03-04 10:46 ` Peter Zijlstra
2025-03-05 3:26 ` Alexei Starovoitov
2025-02-10 9:49 ` Peter Zijlstra
2025-02-10 19:16 ` Ankur Arora
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