From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1793829752; b=cyIEewi7gqAyWNYLb9unOeJ4zLGLl5sjbYShj/kDUtd8UH8ypytZQFW1A5zxSn90sIut jzbgZqa0LeTWuCvzCX6wUNl83sZ5WJI2B21ZdTMXhYRch9qETqngoazA7Q3w4ure3rLBX 8gwV37NaNifadwDPieuL29AHDvtsrPyyXUyeC/uSzx2/m2wB1CLc13qZ5wnVfaXxQa272 Fb9JtI4cF1qLPYkXaXE3Nut7lkxhLuNuJMMsuncgpIOX20xUtH9XpH5xKkT463NijkP5g B2KEGvsd7OxWibw5gVmiGvsOP90BLWjRpGQiZnF2wxtLXeerMRsyoo7lqJ+B0zLmnkg== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793829752; h=Received:DKIM-Signature:From:To:Cc:Subject:Date:Message-ID:X-Mailer: In-Reply-To:References:User-Agent:X-stable:X-Patchwork-Hint: MIME-Version:Content-Transfer-Encoding; bh=SgUTcBh1rplxe11xj9x+fBpEUugKkajGmCYPAe3y15A=; b=T/2fhmjweRwpMwyJYrwtG6XmV+xhFUBS/cbsxjnMSRaPLYLDe71B06taXvEKvkaIBSyE aTLgY93zuNaashGMMVeQ46A7pjbLhqpOG1L0rkZAY+G0d+8pFDIJPb500pwbL4a6Ja50j jRq9It3uGYgkiTcAOKO+ab7KnSoaikpMun4Me7SCdOQ8ABwxVTRteS5c8O8gGoqw8v1Ce +ts0FrUe7NFlKVQMccL2g6mMKPnjuh+hgMtC3dEEeRrLnxhPbL68pgRoRNiuFe6S6gRby SqmWaS2BOtxjD4iIMW91pXIvbG1nVvDfD90GzXMl1zuJMQOJCt2gOqQB1WhNi0JXmyg== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=oRczBNEF; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 8FCF9606C922; Wed, 4 Nov 2026 22:02:32 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key, unprotected) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=oRczBNEF Received: by smtp.kernel.org (Postfix) with ESMTPSA id 2878F1F0093A; Wed, 4 Nov 2026 22:02:32 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1793829752; bh=SgUTcBh1rplxe11xj9x+fBpEUugKkajGmCYPAe3y15A=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=oRczBNEFxZwE3KiUARH6lx/a0FFAZm3jOIGGaFVNKqxUXHnPTz2dD/ghmyErNAqTv DpNOBiFon/3bDGcFR0eHCjiPzMPxkjlSFJGGlKeNdHDFqRYPZOznSeoZNM7wvWQNUl OtxMRV0jGN4VtcLES5EgkUvu/BvLukvvDQyWprLc= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Allison Henderson , Jakub Kicinski , Sasha Levin Subject: [PATCH 6.18 0321/1005] net/rds: unpin MR pages with unpin_user_pages_dirty_lock() Date: Wed, 4 Nov 2026 16:00:54 -0500 Message-ID: <20261104211052.934003421@linuxfoundation.org> X-Mailer: git-send-email 2.56.0 In-Reply-To: <20261104211043.516122098@linuxfoundation.org> References: <20261104211043.516122098@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore X-Mailing-List: patches@lists.linux.dev List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Allison Henderson [ Upstream commit a507023e6ff1d0b4e7aac49b2f547fed0c21ea4e ] The pages backing an RDS memory region are pinned in __rds_rdma_map() with rds_pin_pages(), which uses pin_user_pages_fast(): each page's refcount is biased by GUP_PIN_COUNTING_BIAS to account the pin. The scatterlist is then handed to the IB transport, and the transport releases the pages in __rds_ib_teardown_mr() with set_page_dirty(page); put_page(page); put_page() drops a single reference instead of removing the pin bias, so every MR teardown permanently strands the remaining references and the pages are never freed - a userspace-triggerable memory leak of up to RDS_MAX_MSG_SIZE per RDS_GET_MR/RDS_GET_MR_FOR_DEST call. The conversion to the pin API updated the unpin sites in rdma.c but missed this one on the transport side. Release the pages with unpin_user_pages_dirty_lock(), which removes the pin bias and also dirties the page under the folio lock, closing the truncation race that a bare set_page_dirty() leaves open. Dirtying under the folio lock can sleep, which is safe in every path that reaches __rds_ib_teardown_mr(): the registration-reuse path (rds_ib_map_frmr()) runs in syscall context, and the pool flush (rds_ib_unreg_frmr()) runs under pool->flush_lock, a mutex, and already sleeps in rds_ib_post_inv(). The WARN_ON that guarded the old irq-context set_page_dirty() case is dropped along with it. Signed-off-by: Allison Henderson Link: https://patch.msgid.link/20260730041629.3512480-5-achender@kernel.org Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin --- net/rds/ib_rdma.c | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-) diff --git a/net/rds/ib_rdma.c b/net/rds/ib_rdma.c index 751755cd069e0..36fd8dedbce56 100644 --- a/net/rds/ib_rdma.c +++ b/net/rds/ib_rdma.c @@ -251,9 +251,7 @@ void __rds_ib_teardown_mr(struct rds_ib_mr *ibmr) /* FIXME we need a way to tell a r/w MR * from a r/o MR */ - WARN_ON(!page->mapping && irqs_disabled()); - set_page_dirty(page); - put_page(page); + unpin_user_pages_dirty_lock(&page, 1, true); } kfree(ibmr->sg); -- 2.53.0