From: "Alexei Starovoitov" <alexei.starovoitov@gmail.com>
To: <bot+bpf-ci@kernel.org>, <bpf@vger.kernel.org>
Cc: <daniel@iogearbox.net>, <andrii@kernel.org>, <eddyz87@gmail.com>,
<memxor@gmail.com>, <a.s.protopopov@gmail.com>,
<martin.lau@kernel.org>, <yonghong.song@linux.dev>,
<mason@kernel.org>, <ihor.solodrai@linux.dev>
Subject: Re: [PATCH bpf-next 10/17] bpf: Recognize pointers to functions in read-only maps
Date: Thu, 24 Sep 2026 02:12:01 +0000 [thread overview]
Message-ID: <DLN6KWMU54RL.2ME06QRKZKCQ1@gmail.com> (raw)
In-Reply-To: <7f1587113ee73116a351e6a5316e2b8f7485b1cdb69ab60fd56ae9069e98d767@mail.kernel.org>
On Thu, Sep 24, 2026 at 12:46 AM bot+bpf-ci@kernel.org <bot+bpf-ci@kernel.org> wrote:
>> + while (i < cnt && ptrs[i].map_off < o)
>> + i++;
>> + if (i == cnt || ptrs[i].map_off != o)
>> + goto overlap;
>
> Can reads that don't actually overlap pointers still be rejected here?
> Looking at the bounds-based overlap check, when a vtable-like struct has
> both data and function pointers (e.g., struct { u64 data; void (*fn)(void); }
> with stride 16), reading tbl[i].data gives var_off with offsets 0, 16, 32...
> where every tnum-possible offset is non-pointer data.
That's a limitation of v1,
but sure I'll try to make it work in v2.
>> + if (env->func_ptr_cnt) {
>> + err = check_func_ptr_read(env, reg, off, size, value_regno);
>
> Does a PTR_TO_FUNC loaded from a map force the program to be JITed?
> check_func_ptr_read() marks the register as PTR_TO_FUNC but doesn't set
> env->prog->jit_required. The map still holds the byte offset (e.g. 0x40),
> not a real address until jit_subprogs() patches it.
Will fix in v2: the read of such pointer will set jit_required.
next prev parent reply other threads:[~2026-09-24 2:12 UTC|newest]
Thread overview: 44+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-09-22 1:13 [PATCH bpf-next 00/17] bpf: Indirect calls of bpf subprogs (callx) Alexei Starovoitov
2026-09-22 1:13 ` [PATCH bpf-next 01/17] bpf: Fix infinite loop in check_max_stack_depth() Alexei Starovoitov
2026-09-22 2:01 ` bot+bpf-ci
2026-09-22 2:56 ` Alexei Starovoitov
2026-09-23 22:35 ` Eduard Zingerman
2026-09-22 1:13 ` [PATCH bpf-next 02/17] selftests/bpf: Test recursion through a global function and a callback Alexei Starovoitov
2026-09-22 1:13 ` [PATCH bpf-next 03/17] bpf: Don't fold loads from insn_array maps into constants Alexei Starovoitov
2026-09-23 22:39 ` Eduard Zingerman
2026-09-23 23:12 ` Alexei Starovoitov
2026-09-24 0:19 ` bot+bpf-ci
2026-09-22 1:13 ` [PATCH bpf-next 04/17] bpf: Prepare static analysis passes for callx instruction Alexei Starovoitov
2026-09-23 23:10 ` Eduard Zingerman
2026-09-23 23:51 ` Alexei Starovoitov
2026-09-22 1:13 ` [PATCH bpf-next 05/17] bpf: Add callx instruction to call bpf subprogs indirectly Alexei Starovoitov
2026-09-24 0:09 ` Eduard Zingerman
2026-09-22 1:13 ` [PATCH bpf-next 06/17] bpf: Add callx calls to the call graph Alexei Starovoitov
2026-09-22 1:27 ` sashiko-bot
2026-09-22 2:54 ` Alexei Starovoitov
2026-09-22 1:13 ` [PATCH bpf-next 07/17] bpf, x86: Add JIT support for callx Alexei Starovoitov
2026-09-22 1:27 ` sashiko-bot
2026-09-22 2:53 ` Alexei Starovoitov
2026-09-22 1:13 ` [PATCH bpf-next 08/17] bpf, arm64: " Alexei Starovoitov
2026-09-22 15:05 ` Puranjay Mohan
2026-09-22 1:13 ` [PATCH bpf-next 09/17] bpf: Discover subprogs described by func_info Alexei Starovoitov
2026-09-22 1:13 ` [PATCH bpf-next 10/17] bpf: Recognize pointers to functions in read-only maps Alexei Starovoitov
2026-09-22 1:31 ` sashiko-bot
2026-09-22 3:01 ` Alexei Starovoitov
2026-09-24 0:46 ` bot+bpf-ci
2026-09-24 2:12 ` Alexei Starovoitov [this message]
2026-09-22 1:13 ` [PATCH bpf-next 11/17] libbpf: Support pointers to static functions in data when linking Alexei Starovoitov
2026-09-22 1:13 ` [PATCH bpf-next 12/17] libbpf: Resolve pointers to functions in read-only data Alexei Starovoitov
2026-09-24 0:33 ` bot+bpf-ci
2026-09-24 2:13 ` Alexei Starovoitov
2026-09-22 1:13 ` [PATCH bpf-next 13/17] libbpf: Treat .data.rel.ro as " Alexei Starovoitov
2026-09-22 1:13 ` [PATCH bpf-next 14/17] libbpf: Support pointers to functions in read-only data in light skeleton Alexei Starovoitov
2026-09-22 2:01 ` bot+bpf-ci
2026-09-22 2:55 ` Alexei Starovoitov
2026-09-22 1:13 ` [PATCH bpf-next 15/17] selftests/bpf: Add tests for callx Alexei Starovoitov
2026-09-24 0:33 ` bot+bpf-ci
2026-09-24 2:13 ` Alexei Starovoitov
2026-09-22 1:13 ` [PATCH bpf-next 16/17] selftests/bpf: Add tests for callx through pointers in read-only data Alexei Starovoitov
2026-09-22 2:01 ` bot+bpf-ci
2026-09-24 0:33 ` bot+bpf-ci
2026-09-22 1:13 ` [PATCH bpf-next 17/17] bpf, docs: Document callx instruction Alexei Starovoitov
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