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Peter Anvin" , Ingo Molnar , Jiri Olsa , Masami Hiramatsu , Paulo Andrade , Thomas Gleixner , linux-kernel@vger.kernel.org, x86@kernel.org Subject: Re: [BUG] x86: 32-bit uprobes are broken Message-ID: References: <20260107152716.GG2393663@noisy.programming.kicks-ass.net> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260107152716.GG2393663@noisy.programming.kicks-ass.net> X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.93 On 01/07, Peter Zijlstra wrote: > > On Wed, Jan 07, 2026 at 03:32:53PM +0100, Oleg Nesterov wrote: > > This patch > > > > --- a/kernel/events/uprobes.c > > +++ b/kernel/events/uprobes.c > > @@ -1710,8 +1710,11 @@ static int xol_add_vma(struct mm_struct *mm, struct xol_area *area) > > > > if (!area->vaddr) { > > /* Try to map as high as possible, this is only a hint. */ > > + if (test_thread_flag(TIF_ADDR32)) > > + current_thread_info()->status |= TS_COMPAT; > > area->vaddr = get_unmapped_area(NULL, TASK_SIZE - PAGE_SIZE, > > PAGE_SIZE, 0, 0); > > + current_thread_info()->status &= ~TS_COMPAT; > > if (IS_ERR_VALUE(area->vaddr)) { > > ret = area->vaddr; > > goto fail; > > Urgh. Also I'm a little bit confused; set_personality_ia32(), which is > what sets TIF_ADDR32 (afaict) would also set TS_COMPAT, no? Yep. But TS_COMPAT is per syscall, not per task. It is cleared in arch_exit_to_user_mode_prepare(), in this case after sys_execve() syscall. Oleg.