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Fri, 29 Nov 2024 07:06:33 -0800 (PST) From: Neil Armstrong Date: Fri, 29 Nov 2024 16:06:25 +0100 Subject: [PATCH v2 2/2] OPP: fix dev_pm_opp_find_bw_*() when bandwidth table not initialized Precedence: bulk X-Mailing-List: linux-pm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Message-Id: <20241129-topic-opp-fix-assert-index-check-v2-2-386b2dcbb9a6@linaro.org> References: <20241129-topic-opp-fix-assert-index-check-v2-0-386b2dcbb9a6@linaro.org> In-Reply-To: <20241129-topic-opp-fix-assert-index-check-v2-0-386b2dcbb9a6@linaro.org> To: Viresh Kumar , Nishanth Menon , Stephen Boyd , Manivannan Sadhasivam Cc: Viresh Kumar , linux-pm@vger.kernel.org, linux-kernel@vger.kernel.org, Neil Armstrong X-Mailer: b4 0.14.2 X-Developer-Signature: v=1; a=openpgp-sha256; l=2343; i=neil.armstrong@linaro.org; h=from:subject:message-id; bh=9yHf0KJWm0K/IY4/jKLBMpZERAg9i0/ucu034t8ZUuM=; b=owEBbQKS/ZANAwAKAXfc29rIyEnRAcsmYgBnSdhyA5K9LuQf2hibSwfMOcLoWPeVKDCzr8fh4fDg vEz0EhmJAjMEAAEKAB0WIQQ9U8YmyFYF/h30LIt33NvayMhJ0QUCZ0nYcgAKCRB33NvayMhJ0e0PD/ 423aI0Dmnr1QZ6PDbOOOuhw4LGjo5XIuoi8jI3fIshhu8/Hw1ZIbsxkwOkDKd6+NjTvZhuy/ZMwal1 jeV3NfZykvRRTux3EJ0U0xoE2Zb1jrywxp1q5a5pnI0cdbOWfX239x89gEtMhwC/x3KHFyCsWVyLo5 GjJ86edXwEZSjHbYaoQLhtAI9bSuay94hM+LA2dr1IiGnEUflsGwFO1gwp7rfEh+SSNrHW6igh/Jk6 AItaIdUJTxW+LFosDfo2p5lrt19lvkiSyoOTJ+QOq9o5y9OxpyRy1KYP11WN5e9cqjd5BcVwTL+3f0 KIYr6MxOK4ncX7q2CaHtE1bMhqg8520W2P6lNzUk0jrLR36fq0lL2+KohC2bOvHOYiN8VX7pMpF6Gf vFDiENUjQpOn5snFoX5wM5FWqt/Q7MCf1CRNGPfU0z4xLgPmPgY/6RihvCctYduv+v/8WcCWh5Hmmq LE1rvSRU3h9/LD9kqoXKGkjCg4y/VOw7bh+W2L9ntR101JgDaHjlfbrNus6O67LNRY6keSBHx3g5AQ 76QZIqPAG8bHg5jfAZt69k384Satzq1UNrFIyH/NCKfW2ragquOCFDCBHn79teS2OlZBnDjwDmal7h HKBKwK8bx4XkkEakV28IEk0YSuhUlInb3D+jsAXUJj6DOW1gErL4PpglS+Ag== X-Developer-Key: i=neil.armstrong@linaro.org; a=openpgp; fpr=89EC3D058446217450F22848169AB7B1A4CFF8AE If a driver calls dev_pm_opp_find_bw_ceil/floor() the retrieve bandwidth from the OPP table but the bandwidth table was not created because the interconnect properties were missing in the OPP consumer node, the kernel will crash with: Unable to handle kernel NULL pointer dereference at virtual address 0000000000000004 ... pc : _read_bw+0x8/0x10 lr : _opp_table_find_key+0x9c/0x174 ... Call trace: _read_bw+0x8/0x10 (P) _opp_table_find_key+0x9c/0x174 (L) _find_key+0x98/0x168 dev_pm_opp_find_bw_ceil+0x50/0x88 ... In order to fix the crash, create an assert function to check if the bandwidth table was created before trying to get a bandwidth with _read_bw(). Fixes: add1dc094a74 ("OPP: Use generic key finding helpers for bandwidth key") Signed-off-by: Neil Armstrong --- drivers/opp/core.c | 14 ++++++++++++-- 1 file changed, 12 insertions(+), 2 deletions(-) diff --git a/drivers/opp/core.c b/drivers/opp/core.c index 52c6a45ceb7479c3ef0ed97ab43a37546d695c7f..c7d16b2c5110089aeb35012be1dc35dfd209963e 100644 --- a/drivers/opp/core.c +++ b/drivers/opp/core.c @@ -114,6 +114,14 @@ static bool assert_clk_index(struct opp_table *opp_table, int index) return opp_table->clk_count > index; } +/* + * Returns true if bandwidth table is large enough to contain the bandwidth index. + */ +static bool assert_bandwidth_index(struct opp_table *opp_table, int index) +{ + return opp_table->path_count > index; +} + /** * dev_pm_opp_get_bw() - Gets the bandwidth corresponding to an opp * @opp: opp for which bandwidth has to be returned for @@ -913,7 +921,8 @@ struct dev_pm_opp *dev_pm_opp_find_bw_ceil(struct device *dev, unsigned int *bw, unsigned long temp = *bw; struct dev_pm_opp *opp; - opp = _find_key_ceil(dev, &temp, index, true, _read_bw, NULL); + opp = _find_key_ceil(dev, &temp, index, true, _read_bw, + assert_bandwidth_index); *bw = temp; return opp; } @@ -944,7 +953,8 @@ struct dev_pm_opp *dev_pm_opp_find_bw_floor(struct device *dev, unsigned long temp = *bw; struct dev_pm_opp *opp; - opp = _find_key_floor(dev, &temp, index, true, _read_bw, NULL); + opp = _find_key_floor(dev, &temp, index, true, _read_bw, + assert_bandwidth_index); *bw = temp; return opp; }