From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mout.gmx.net (mout.gmx.net [212.227.15.19]) (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 5F5D81F76D8; Wed, 8 Jan 2025 09:55:45 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=212.227.15.19 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1736330149; cv=none; b=ImCObASrOeu+QbwiIVmbJjNeAK6V1KPPVtMch3m/ezTSGnFKi6L5656siuFLKafMLfF3aVMggHQhdM+H/StKvpOOUhIxmeXjwQ+CW3o/FYms1wQ/yR20kPe/AnFnqqntOaTVyKJGlx/xs5bznz6DRWxIfOeMFvOMMIUqKY12Kpw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1736330149; c=relaxed/simple; bh=LOcLJoHuXGeCsqWi41zWQyajyaxK80/wSjjIMZBnptY=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=F/NAJOXW4chJLKWL82eSnX+LR+2T3e9Ko1qW+0Pw71kW0jIAHrFevnajaL83vnOoFJh+u0ENXpCAJXbUvrL9hsR0d1A3FP+BMIN0b0tQ1dLsqo19+6OpWi1e2YneUrWhu6u3E43cSDc4lnDv/lSrmrN6jyOy9toR6VdEyX0WWzY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=gmx.de; spf=pass smtp.mailfrom=gmx.de; dkim=pass (2048-bit key) header.d=gmx.de header.i=deller@gmx.de header.b=LKYR3CmT; arc=none smtp.client-ip=212.227.15.19 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=gmx.de Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmx.de Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmx.de header.i=deller@gmx.de header.b="LKYR3CmT" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmx.de; s=s31663417; t=1736330107; x=1736934907; i=deller@gmx.de; bh=h+FDPMNYxrfjF0i2mQ0uoWU9n5W/BNw1XId/Jy4xp1w=; h=X-UI-Sender-Class:Message-ID:Date:MIME-Version:Subject:To:Cc: References:From:In-Reply-To:Content-Type: Content-Transfer-Encoding:cc:content-transfer-encoding: content-type:date:from:message-id:mime-version:reply-to:subject: to; b=LKYR3CmTAnqKAJfB0F+Ml25i8CNqE6DQqynPEeG2J2j6gZxVXRlDZ4WSDp/r2/jM 7b1tcqQjJ0p942+xZWgtH8n0N8Qw3Ie57BoHJZchtLb/7AdsTwGHycNDWHgPsscbU mb8o+KbgkkHg88dtI2RExiVQTYBMUXW0plFt+auVQ8ir2yBMW1BwJ2VY3IFzazJns 8wQ03WeH9RLLF99Rz9lTbGCjshrTejn6fKSmGM/a7HrC/vxHkhmAIE5I6OfUTHNOZ 1WFekoL7H0D/Yz9oOmYHgIkjlj0ehdgcBKppc9oEVPTfT618sjPutGYcDVjCyaR2h hwHC9ffGJs4Ltn9htQ== X-UI-Sender-Class: 724b4f7f-cbec-4199-ad4e-598c01a50d3a Received: from [10.8.0.6] ([78.94.87.245]) by mail.gmx.net (mrgmx004 [212.227.17.190]) with ESMTPSA (Nemesis) id 1MYNJg-1t05yS2wRG-00MHsk; Wed, 08 Jan 2025 10:55:06 +0100 Message-ID: <6e8ef32e-6698-496e-a9e4-09f0ade5f264@gmx.de> Date: Wed, 8 Jan 2025 10:55:04 +0100 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v3 01/28] module: Extend the preempt disabled section in dereference_symbol_descriptor(). To: Sebastian Andrzej Siewior , linux-modules@vger.kernel.org, linux-kernel@vger.kernel.org Cc: Daniel Gomez , Luis Chamberlain , "Paul E . McKenney" , Peter Zijlstra , Petr Pavlu , Sami Tolvanen , Thomas Gleixner , "James E.J. Bottomley" , Christophe Leroy , Madhavan Srinivasan , Michael Ellerman , Naveen N Rao , Nicholas Piggin , Sergey Senozhatsky , linux-parisc@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, Sergey Senozhatsky References: <20250108090457.512198-1-bigeasy@linutronix.de> <20250108090457.512198-2-bigeasy@linutronix.de> Content-Language: en-US From: Helge Deller Autocrypt: addr=deller@gmx.de; keydata= xsFNBF3Ia3MBEAD3nmWzMgQByYAWnb9cNqspnkb2GLVKzhoH2QD4eRpyDLA/3smlClbeKkWT HLnjgkbPFDmcmCz5V0Wv1mKYRClAHPCIBIJgyICqqUZo2qGmKstUx3pFAiztlXBANpRECgwJ r+8w6mkccOM9GhoPU0vMaD/UVJcJQzvrxVHO8EHS36aUkjKd6cOpdVbCt3qx8cEhCmaFEO6u CL+k5AZQoABbFQEBocZE1/lSYzaHkcHrjn4cQjc3CffXnUVYwlo8EYOtAHgMDC39s9a7S90L 69l6G73lYBD/Br5lnDPlG6dKfGFZZpQ1h8/x+Qz366Ojfq9MuuRJg7ZQpe6foiOtqwKym/zV dVvSdOOc5sHSpfwu5+BVAAyBd6hw4NddlAQUjHSRs3zJ9OfrEx2d3mIfXZ7+pMhZ7qX0Axlq Lq+B5cfLpzkPAgKn11tfXFxP+hcPHIts0bnDz4EEp+HraW+oRCH2m57Y9zhcJTOJaLw4YpTY GRUlF076vZ2Hz/xMEvIJddRGId7UXZgH9a32NDf+BUjWEZvFt1wFSW1r7zb7oGCwZMy2LI/G aHQv/N0NeFMd28z+deyxd0k1CGefHJuJcOJDVtcE1rGQ43aDhWSpXvXKDj42vFD2We6uIo9D 1VNre2+uAxFzqqf026H6cH8hin9Vnx7p3uq3Dka/Y/qmRFnKVQARAQABzRxIZWxnZSBEZWxs ZXIgPGRlbGxlckBnbXguZGU+wsGRBBMBCAA7AhsDBQsJCAcCBhUKCQgLAgQWAgMBAh4BAheA FiEERUSCKCzZENvvPSX4Pl89BKeiRgMFAl3J1zsCGQEACgkQPl89BKeiRgNK7xAAg6kJTPje uBm9PJTUxXaoaLJFXbYdSPfXhqX/BI9Xi2VzhwC2nSmizdFbeobQBTtRIz5LPhjk95t11q0s uP5htzNISPpwxiYZGKrNnXfcPlziI2bUtlz4ke34cLK6MIl1kbS0/kJBxhiXyvyTWk2JmkMi REjR84lCMAoJd1OM9XGFOg94BT5aLlEKFcld9qj7B4UFpma8RbRUpUWdo0omAEgrnhaKJwV8 qt0ULaF/kyP5qbI8iA2PAvIjq73dA4LNKdMFPG7Rw8yITQ1Vi0DlDgDT2RLvKxEQC0o3C6O4 iQq7qamsThLK0JSDRdLDnq6Phv+Yahd7sDMYuk3gIdoyczRkXzncWAYq7XTWl7nZYBVXG1D8 gkdclsnHzEKpTQIzn/rGyZshsjL4pxVUIpw/vdfx8oNRLKj7iduf11g2kFP71e9v2PP94ik3 Xi9oszP+fP770J0B8QM8w745BrcQm41SsILjArK+5mMHrYhM4ZFN7aipK3UXDNs3vjN+t0zi qErzlrxXtsX4J6nqjs/mF9frVkpv7OTAzj7pjFHv0Bu8pRm4AyW6Y5/H6jOup6nkJdP/AFDu 5ImdlA0jhr3iLk9s9WnjBUHyMYu+HD7qR3yhX6uWxg2oB2FWVMRLXbPEt2hRGq09rVQS7DBy dbZgPwou7pD8MTfQhGmDJFKm2jvOwU0EXchrcwEQAOsDQjdtPeaRt8EP2pc8tG+g9eiiX9Sh rX87SLSeKF6uHpEJ3VbhafIU6A7hy7RcIJnQz0hEUdXjH774B8YD3JKnAtfAyuIU2/rOGa/v UN4BY6U6TVIOv9piVQByBthGQh4YHhePSKtPzK9Pv/6rd8H3IWnJK/dXiUDQllkedrENXrZp eLUjhyp94ooo9XqRl44YqlsrSUh+BzW7wqwfmu26UjmAzIZYVCPCq5IjD96QrhLf6naY6En3 ++tqCAWPkqKvWfRdXPOz4GK08uhcBp3jZHTVkcbo5qahVpv8Y8mzOvSIAxnIjb+cklVxjyY9 dVlrhfKiK5L+zA2fWUreVBqLs1SjfHm5OGuQ2qqzVcMYJGH/uisJn22VXB1c48yYyGv2HUN5 lC1JHQUV9734I5cczA2Gfo27nTHy3zANj4hy+s/q1adzvn7hMokU7OehwKrNXafFfwWVK3OG 1dSjWtgIv5KJi1XZk5TV6JlPZSqj4D8pUwIx3KSp0cD7xTEZATRfc47Yc+cyKcXG034tNEAc xZNTR1kMi9njdxc1wzM9T6pspTtA0vuD3ee94Dg+nDrH1As24uwfFLguiILPzpl0kLaPYYgB wumlL2nGcB6RVRRFMiAS5uOTEk+sJ/tRiQwO3K8vmaECaNJRfJC7weH+jww1Dzo0f1TP6rUa fTBRABEBAAHCwXYEGAEIACAWIQRFRIIoLNkQ2+89Jfg+Xz0Ep6JGAwUCXchrcwIbDAAKCRA+ Xz0Ep6JGAxtdEAC54NQMBwjUNqBNCMsh6WrwQwbg9tkJw718QHPw43gKFSxFIYzdBzD/YMPH l+2fFiefvmI4uNDjlyCITGSM+T6b8cA7YAKvZhzJyJSS7pRzsIKGjhk7zADL1+PJei9p9idy RbmFKo0dAL+ac0t/EZULHGPuIiavWLgwYLVoUEBwz86ZtEtVmDmEsj8ryWw75ZIarNDhV74s BdM2ffUJk3+vWe25BPcJiaZkTuFt+xt2CdbvpZv3IPrEkp9GAKof2hHdFCRKMtgxBo8Kao6p Ws/Vv68FusAi94ySuZT3fp1xGWWf5+1jX4ylC//w0Rj85QihTpA2MylORUNFvH0MRJx4mlFk XN6G+5jIIJhG46LUucQ28+VyEDNcGL3tarnkw8ngEhAbnvMJ2RTx8vGh7PssKaGzAUmNNZiG MB4mPKqvDZ02j1wp7vthQcOEg08z1+XHXb8ZZKST7yTVa5P89JymGE8CBGdQaAXnqYK3/yWf FwRDcGV6nxanxZGKEkSHHOm8jHwvQWvPP73pvuPBEPtKGLzbgd7OOcGZWtq2hNC6cRtsRdDx 4TAGMCz4j238m+2mdbdhRh3iBnWT5yPFfnv/2IjFAk+sdix1Mrr+LIDF++kiekeq0yUpDdc4 ExBy2xf6dd+tuFFBp3/VDN4U0UfG4QJ2fg19zE5Z8dS4jGIbLg== In-Reply-To: <20250108090457.512198-2-bigeasy@linutronix.de> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: quoted-printable X-Provags-ID: V03:K1:NhXedhMSLlZ7ulSfMLkndsPoKhwqFocc8tNYosRsVObc1ugZJFU 4P/lozizkTV2AndWGOCWRIr4tm8hvnaO6v8sy0/QbHSC+zWUo7IWH2ru+foZTuHQryj6Zqr warogruhQdz1S2NOSGHAmpl1qrGvQnbQT5tE2UO/fi1BQmvYnlVlfS21cRarHDYwDpKrjKz TnsrEWWNiZegEzyRTEbsQ== X-Spam-Flag: NO UI-OutboundReport: notjunk:1;M01:P0:6AZrJ/KbjLU=;ub3kUj1c3dF3BTYf0wjHg+aHhFu ebYetpUe1Zpunwk5noPXayYJZcIT7xEEREgQPwehB0sVXuEh3msskx47rCpHotSRgbV6dnFC7 mYtI/6z2OQEGAza/cNCBJu/xI+/n+oDGMqWtfnxJAKtLTqp+iiQPO494IuScgglISYG6St8ZD 08yzhM4pA5FZ10ig7nJ4X/cKtWw4hINZ8cnxV1yGk0fSGnrxgY6K6BN/P1ZI15yhq50Fr8YeG ymylELXaGCp8o1SWlkpYD6L/BPQcNp1i4inKSsPB/HwyhwuRv+SMPRbKOOy3Ulcqg23LVY+sG MueIPzCA25O7pwRF/77EEeDuOqhm5wNKxGYdT4zh41hID9zPEwUl9xmWpkYA5736CUDUBQPUT F4KbAWXLtwu+DpCXtwqVpPncaAOULidLsWaB44NzH5vMizK5ZNsyHdDzfqAelD6C6iuI0IJ4X DmPzP7GUGNVwAfpd2Q8bmb4D1chJ3k1cljXBcdY/JEKrlH9jbCfNJPfPSDTUjGYfe1E88hArU 7vM5/xZsEjVcyVR8bykZKyInaRu8HrBAztfMYAHQYmGq6s8E++xK4GLecMDECcBm7EQLlSyGN 2lhi/2nri/rcbvcNpI2OIHOyej47vWnZMH5xdZ8/1OmZovh2aTrkP6PnoGJxj0DP+p3WpmIyk HatAKEMLAcEXGHfK05PGQ8jGUpC+73Anei54Xn0d6k5LX/oix2GeBkMuGpN+3W48K1rws8Chy DlFz71wlIXJ3viYbOkgaj8Va/scnIIGZrLaywkQHM9zPaDYkn7ejrA5KxCS02wt3Kcue7PktB Ak6DIs8a0tL55AwXD76HB64kbK7CQvS3daBIP+BAn+Hvu5dGm62SljUpGCgN+vwNDIacHbNt+ Eh6ICY3AVzXLBduDNFPkSrzN7j5oP1yNWm39qYU0T23IT7oIkqXNs82S4vvjHUJsOh8IRdMLJ /O4dUP/GjYECPC0ayOEIkPFcXQWoH79ruZw7WFGCJtnyPMODNKkBSbBqiZCgSYv28eXDF+/cM 1/WGaiXuq5CssOktRjqP2gUyIuR8/WmXhdFAYo4CugGhUE2nsCYj/DJ2VKDuJI5fOic1yo66Z SJCRL24LwUJv7Mw86Dx82GrS1TgdaM On 1/8/25 10:04, Sebastian Andrzej Siewior wrote: > dereference_symbol_descriptor() needs to obtain the module pointer > belonging to pointer in order to resolve that pointer. > The returned mod pointer is obtained under RCU-sched/ preempt_disable() > guarantees and needs to be used within this section to ensure that the > module is not removed in the meantime. > > Extend the preempt_disable() section to also cover > dereference_module_function_descriptor(). > > Fixes: 04b8eb7a4ccd9 ("symbol lookup: introduce dereference_symbol_descr= iptor()") > Cc: James E.J. Bottomley > Cc: Christophe Leroy > Cc: Helge Deller > Cc: Madhavan Srinivasan > Cc: Michael Ellerman > Cc: Naveen N Rao > Cc: Nicholas Piggin > Cc: Sergey Senozhatsky > Cc: linux-parisc@vger.kernel.org > Cc: linuxppc-dev@lists.ozlabs.org > Reviewed-by: Sergey Senozhatsky > Acked-by: Peter Zijlstra (Intel) > Signed-off-by: Sebastian Andrzej Siewior Nice catch. Acked-by: Helge Deller This patch really should be backported. Can you add a Cc: stable tag? Helge > --- > include/linux/kallsyms.h | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/include/linux/kallsyms.h b/include/linux/kallsyms.h > index c3f075e8f60cb..1c6a6c1704d8d 100644 > --- a/include/linux/kallsyms.h > +++ b/include/linux/kallsyms.h > @@ -57,10 +57,10 @@ static inline void *dereference_symbol_descriptor(vo= id *ptr) > > preempt_disable(); > mod =3D __module_address((unsigned long)ptr); > - preempt_enable(); > > if (mod) > ptr =3D dereference_module_function_descriptor(mod, ptr); > + preempt_enable(); > #endif > return ptr; > }