From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 7EA58214745; Wed, 25 Sep 2024 12:12:35 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1727266355; cv=none; b=djzzxbvZUjT6Qhg/9HWyrax1KlXohy2mA8Ex2cn+4Zm2RqkY6LSzUiA08bT/5CEYB+nSf4E8twPtErlxkiVkPYoCrdys8b9L1palRmboGfHNFSEU9uBFokGw3l1d5slztdhzyvAd1yrD2BUAsKSwT7yLaOX3Y8CB865LOtE2zeA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1727266355; c=relaxed/simple; bh=lPh4XGxlZ5+6V37UHzwAasgbpKcJw58Lg8Yn7gbFo+I=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=IHrn1P8t4XJ5WrRI4LfLSneSblF5HAXOaK5/MQyC8bF09jshuQ7LL0Wk0pm0T4yg2k8OUCsWGYkNCpCkpDSpiQ2UWL70mk/f0upuN3OtM6q8pfE23RTOewHj/6SO3R4MowIR6SXRruAn1Foj+GMYe8CV7BQ2zY6CU5ri5S2eqU8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=hGBbEmuf; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="hGBbEmuf" Received: by smtp.kernel.org (Postfix) with ESMTPSA id BCFD4C4CEC3; Wed, 25 Sep 2024 12:12:33 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1727266355; bh=lPh4XGxlZ5+6V37UHzwAasgbpKcJw58Lg8Yn7gbFo+I=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=hGBbEmufdnyB3oJTKtEfXqfx8Bz0pr4cTz9OFHFKMO0VpAc547f9SIjX1yQxgA1Tt zohSYXTsW5FtSVq0HmtkXL72ymPGSd0qRLMi8nXeyisV5RP0W0iBTPLGQRfQ7sZlD/ wtqxZNW28a2EjTvRqNppn/UteF5PzLSr1i+nrdwUHmi/RazAzr1Ln/gNexFhgASm33 abaGn35UAnKXH+ZX20u6mdITlnpf02Dgd+TqKjwtgJjPn0rSer5kt8bnJ7Orlhmqi9 4C5nr9+1OZgf1EbP/PtT6+OMCR++W8JqzqOys4JZT0ivrAtirnXPYQKmDzQ2eIucFK ZFj562Bta94hg== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Konstantin Ovsepian , Breno Leitao , Tejun Heo , Jens Axboe , Sasha Levin , josef@toxicpanda.com, cgroups@vger.kernel.org, linux-block@vger.kernel.org Subject: [PATCH AUTOSEL 6.6 025/139] blk_iocost: fix more out of bound shifts Date: Wed, 25 Sep 2024 08:07:25 -0400 Message-ID: <20240925121137.1307574-25-sashal@kernel.org> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20240925121137.1307574-1-sashal@kernel.org> References: <20240925121137.1307574-1-sashal@kernel.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore X-stable-base: Linux 6.6.52 Content-Transfer-Encoding: 8bit From: Konstantin Ovsepian [ Upstream commit 9bce8005ec0dcb23a58300e8522fe4a31da606fa ] Recently running UBSAN caught few out of bound shifts in the ioc_forgive_debts() function: UBSAN: shift-out-of-bounds in block/blk-iocost.c:2142:38 shift exponent 80 is too large for 64-bit type 'u64' (aka 'unsigned long long') ... UBSAN: shift-out-of-bounds in block/blk-iocost.c:2144:30 shift exponent 80 is too large for 64-bit type 'u64' (aka 'unsigned long long') ... Call Trace: dump_stack_lvl+0xca/0x130 __ubsan_handle_shift_out_of_bounds+0x22c/0x280 ? __lock_acquire+0x6441/0x7c10 ioc_timer_fn+0x6cec/0x7750 ? blk_iocost_init+0x720/0x720 ? call_timer_fn+0x5d/0x470 call_timer_fn+0xfa/0x470 ? blk_iocost_init+0x720/0x720 __run_timer_base+0x519/0x700 ... Actual impact of this issue was not identified but I propose to fix the undefined behaviour. The proposed fix to prevent those out of bound shifts consist of precalculating exponent before using it the shift operations by taking min value from the actual exponent and maximum possible number of bits. Reported-by: Breno Leitao Signed-off-by: Konstantin Ovsepian Acked-by: Tejun Heo Link: https://lore.kernel.org/r/20240822154137.2627818-1-ovs@ovs.to Signed-off-by: Jens Axboe Signed-off-by: Sasha Levin --- block/blk-iocost.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) diff --git a/block/blk-iocost.c b/block/blk-iocost.c index 0dca77591d66c..c3cb9c20b306c 100644 --- a/block/blk-iocost.c +++ b/block/blk-iocost.c @@ -2076,7 +2076,7 @@ static void ioc_forgive_debts(struct ioc *ioc, u64 usage_us_sum, int nr_debtors, struct ioc_now *now) { struct ioc_gq *iocg; - u64 dur, usage_pct, nr_cycles; + u64 dur, usage_pct, nr_cycles, nr_cycles_shift; /* if no debtor, reset the cycle */ if (!nr_debtors) { @@ -2138,10 +2138,12 @@ static void ioc_forgive_debts(struct ioc *ioc, u64 usage_us_sum, int nr_debtors, old_debt = iocg->abs_vdebt; old_delay = iocg->delay; + nr_cycles_shift = min_t(u64, nr_cycles, BITS_PER_LONG - 1); if (iocg->abs_vdebt) - iocg->abs_vdebt = iocg->abs_vdebt >> nr_cycles ?: 1; + iocg->abs_vdebt = iocg->abs_vdebt >> nr_cycles_shift ?: 1; + if (iocg->delay) - iocg->delay = iocg->delay >> nr_cycles ?: 1; + iocg->delay = iocg->delay >> nr_cycles_shift ?: 1; iocg_kick_waitq(iocg, true, now); -- 2.43.0