From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from desiato.infradead.org (desiato.infradead.org [90.155.92.199]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 43C7136403C; Thu, 5 Feb 2026 11:12:16 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=90.155.92.199 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1770289937; cv=none; b=QEoC26mKZq7pjQrSA2P7ueypYdzYaYmd9V+4+EKCc8UjU1/+vLbu7BZzhKi3+5n7pjR1O0KWeNNz1J25MNcAricyoxZRTp+XKKY4msfthHMNHiJPLrO16T3o1tr7btUu60h3e+2Y1kK1YmZ3PNgdAa9RZEuClkDOHEG2tlVOzNo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1770289937; c=relaxed/simple; bh=lMERKrA9f3KGVWmy99XaNMxgdqlQA5Wi4Qq4CD7YVVQ=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=MzZjphhzjUcFwh7rHwl2AncPgQmuwZj+jUhWFGgxaC2o2w72ckh4rfZVsE1GAOeIC77b2pFEuHUUSr+YKFkj5Pa6QexixtxW8Z3YRhX96OAu8fW1gQ20JVse3ftyRIhYwFWk3LEugzWPMdC6puFF8uF7rp1UHdQ4VkZN98HQ7Fs= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=infradead.org; spf=none smtp.mailfrom=infradead.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b=HND0avhC; arc=none smtp.client-ip=90.155.92.199 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=infradead.org Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=infradead.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="HND0avhC" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=desiato.20200630; h=In-Reply-To:Content-Transfer-Encoding: Content-Type:MIME-Version:References:Message-ID:Subject:Cc:To:From:Date: Sender:Reply-To:Content-ID:Content-Description; bh=a62NaDchmNolr46mg9fk31y1C9I0rDLZ5Mi3QgshveM=; b=HND0avhC9w3zYHP4P9BvSeJVcN VIDSta45yFI0Q/oOr7Rc9d7aFa5b0eQQtXIs8IPwvjZYtlcqdeo2lM3CAbij96rpFs6mAMUhHDkmc Xkzd8XPoOQKSRDVxh2EnSGKQTSKkgd0pfd/WlJNQXdrf2yuj3RGhKKiC3f3jYBhOzWaPp2oT3L6rz VGDCcroG2GBd6NRX8CIiGdaAx2aR1WoUHgrlK8kU4HZjU/c47yFXBRoOMNaWDbiWzrx8RaXZTBxo2 /FNF0sw6ho1JBz9i8gMzwgG7daWVgTz5Mn+JvL/lO0szwUfVGbr6JxIGFYZpu3RFfDscIvkmq0mhr e5sA8twg==; Received: from 2001-1c00-8d85-5700-266e-96ff-fe07-7dcc.cable.dynamic.v6.ziggo.nl ([2001:1c00:8d85:5700:266e:96ff:fe07:7dcc] helo=noisy.programming.kicks-ass.net) by desiato.infradead.org with esmtpsa (Exim 4.98.2 #2 (Red Hat Linux)) id 1vnxHN-0000000215K-1DTF; Thu, 05 Feb 2026 11:12:09 +0000 Received: by noisy.programming.kicks-ass.net (Postfix, from userid 1000) id CBBB9300BD2; Thu, 05 Feb 2026 12:12:08 +0100 (CET) Date: Thu, 5 Feb 2026 12:12:08 +0100 From: Peter Zijlstra To: Carlos =?iso-8859-1?Q?L=F3pez?= Cc: linux-trace-kernel@vger.kernel.org, linux-perf-users@vger.kernel.org, Masami Hiramatsu , Oleg Nesterov , Ingo Molnar , Arnaldo Carvalho de Melo , Namhyung Kim , Mark Rutland , Alexander Shishkin , Jiri Olsa , Ian Rogers , Adrian Hunter , James Clark , "open list:UPROBES" Subject: Re: [PATCH] uprobes: replace deprecated kmap_atomic() with kmap_local_page() Message-ID: <20260205111208.GK232055@noisy.programming.kicks-ass.net> References: <20260205105725.298340-1-clopez@suse.de> Precedence: bulk X-Mailing-List: linux-trace-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20260205105725.298340-1-clopez@suse.de> On Thu, Feb 05, 2026 at 11:57:25AM +0100, Carlos López wrote: > kmap_atomic() has been deprecated for a few years, and kmap_local_page() > should be used instead, so replace it. Since the uprobes code relied on > kmap_atomic() disabling page faults to access user pages, add the > required calls to keep the existing behavior. Are those pagefault_disable()s really needed here, or is this just cargo-culting? > Signed-off-by: Carlos López > --- > kernel/events/uprobes.c | 22 ++++++++++++++++------ > 1 file changed, 16 insertions(+), 6 deletions(-) > > diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c > index d546d32390a8..38898435acfe 100644 > --- a/kernel/events/uprobes.c > +++ b/kernel/events/uprobes.c > @@ -179,16 +179,24 @@ bool __weak is_trap_insn(uprobe_opcode_t *insn) > > void uprobe_copy_from_page(struct page *page, unsigned long vaddr, void *dst, int len) > { > - void *kaddr = kmap_atomic(page); > + void *kaddr = kmap_local_page(page); > + > + pagefault_disable(); > memcpy(dst, kaddr + (vaddr & ~PAGE_MASK), len); > - kunmap_atomic(kaddr); > + pagefault_enable(); > + > + kunmap_local(kaddr); > } > > static void copy_to_page(struct page *page, unsigned long vaddr, const void *src, int len) > { > - void *kaddr = kmap_atomic(page); > + void *kaddr = kmap_local_page(page); > + > + pagefault_disable(); > memcpy(kaddr + (vaddr & ~PAGE_MASK), src, len); > - kunmap_atomic(kaddr); > + pagefault_enable(); > + > + kunmap_local(kaddr); > } > > static int verify_opcode(struct page *page, unsigned long vaddr, uprobe_opcode_t *insn, > @@ -323,9 +331,10 @@ __update_ref_ctr(struct mm_struct *mm, unsigned long vaddr, short d) > return ret == 0 ? -EBUSY : ret; > } > > - kaddr = kmap_atomic(page); > + kaddr = kmap_local_page(page); > ptr = kaddr + (vaddr & ~PAGE_MASK); > > + pagefault_disable(); > if (unlikely(*ptr + d < 0)) { > pr_warn("ref_ctr going negative. vaddr: 0x%lx, " > "curr val: %d, delta: %d\n", vaddr, *ptr, d); > @@ -336,7 +345,8 @@ __update_ref_ctr(struct mm_struct *mm, unsigned long vaddr, short d) > *ptr += d; > ret = 0; > out: > - kunmap_atomic(kaddr); > + pagefault_enable(); > + kunmap_local(kaddr); > put_page(page); > return ret; > } > > base-commit: f14faaf3a1fb3b9e4cf2e56269711fb85fba9458 > -- > 2.51.0 >