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Fri, 22 May 2020 10:15:23 +0000 (GMT) From: Marek Szyprowski To: linux-pm@vger.kernel.org, linux-i2c@vger.kernel.org, linux-kernel@vger.kernel.org Cc: Marek Szyprowski , Wolfram Sang , Bibby Hsieh , Tomasz Figa , Bartosz Golaszewski , srv_heupstream@mediatek.com, Bartlomiej Zolnierkiewicz , linux-samsung-soc@vger.kernel.org Subject: [PATCH] i2c: core: fix NULL pointer dereference in suspend/resume callbacks Date: Fri, 22 May 2020 12:13:27 +0200 Message-Id: <20200522101327.13456-1-m.szyprowski@samsung.com> X-Mailer: git-send-email 2.17.1 X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFmpnleLIzCtJLcpLzFFi42LZduznOV2bZcfjDG6dV7HYOGM9q8WXuadY LGZumMFi0fH3C6PF5V1z2Cw+9x5htJhxfh+Txdojd9ktpt8Vsvjc+o/NYuWJWcwO3B7vb7Sy e8xuuMji0XJyP4tH35ZVjB4nTz1h8fi8SS6ALYrLJiU1J7MstUjfLoEr48rJ66wFT5Qq1k+6 wtLAuFW2i5GDQ0LAROL2NK4uRi4OIYEVjBLn+w8zQzhfGCVuNM9hhXA+M0q8X3+HpYuRE6xj 291GJhBbSGA5o8TfIw5wHfPvfgIrYhMwlOh628UGYosIhEt8uXGbDaSIWeAUk8S1/72MIAlh gTCJV78fsILYLAKqEp9+PQebyitgK/Hl3h1miG3yEqs3HAC7SULgN5vE1ocXoBIuEkeWr4ay hSVeHd/CDmHLSJye3MMC0dDMKPHw3Fp2CKeHUeJy0wxGiCpriTvnfrGBgoBZQFNi/S59iLCj xKa/V5ghIcMnceOtIEiYGcictG06VJhXoqNNCKJaTWLW8XVwaw9euAR1jofE2xUnGSEhFCtx 6fkX5gmMcrMQdi1gZFzFKJ5aWpybnlpslJdarlecmFtcmpeul5yfu4kRmDxO/zv+ZQfjrj9J hxgFOBiVeHgfJB+LE2JNLCuuzD3EKMHBrCTCu5D/aJwQb0piZVVqUX58UWlOavEhRmkOFiVx XuNFL2OFBNITS1KzU1MLUotgskwcnFINjCZsCueNLx1Zel+yOfUZx7yYNK3DMxNv5Zi/bnP7 MZn95g0e7qr+A3GJ7x2Ent4zC/iUsujJFk7j/t9Tgy7eaKp9oBqovlE9Xb5BdVbX4UxHfrtq QZlfe5Pdp7ca8q14W3h1c3395eaJHZGmOQffVckLGv/29UyQtffLfOpnUyWvJ7xFRPe+Ektx RqKhFnNRcSIAc7kAlhoDAAA= X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFrrHLMWRmVeSWpSXmKPExsVy+t/xu7o2y47HGdw6ym2xccZ6Vosvc0+x WMzcMIPFouPvF0aLy7vmsFl87j3CaDHj/D4mi7VH7rJbTL8rZPG59R+bxcoTs5gduD3e32hl 95jdcJHFo+XkfhaPvi2rGD1OnnrC4vF5k1wAW5SeTVF+aUmqQkZ+cYmtUrShhZGeoaWFnpGJ pZ6hsXmslZGpkr6dTUpqTmZZapG+XYJexpWT11kLnihVrJ90haWBcatsFyMnh4SAicS2u41M XYxcHEICSxklXn7rZ4RIyEicnNbACmELS/y51sUGUfSJUeLGhU5mkASbgKFE11uQBCeHiECk xOu9K8GKmAUuMEkcePwSrEhYIETiy8uL7CA2i4CqxKdfz5lAbF4BW4kv9+4wQ2yQl1i94QDz BEaeBYwMqxhFUkuLc9Nzi430ihNzi0vz0vWS83M3MQLDdtuxn1t2MHa9Cz7EKMDBqMTD+yD5 WJwQa2JZcWXuIUYJDmYlEd6F/EfjhHhTEiurUovy44tKc1KLDzGaAi2fyCwlmpwPjKm8knhD U0NzC0tDc2NzYzMLJXHeDoGDMUIC6YklqdmpqQWpRTB9TBycUg2MPRPX/litvKYn8V5u8NSJ 1aGexuaKDixSaxMXWhocquR0uewg/eUQe2zjk6uXnlzdN2Ebh/M8Ed7M07trPjA/ZU0J+/Iv f1/98j0imSvX30i8wcwZnchj0apSryf1qqb8gysji6/2Np64O51tVZOkfQUNma/M91/Eeey3 QpDP8vdquc0W9xOUWIozEg21mIuKEwFeZN0KcQIAAA== X-CMS-MailID: 20200522101524eucas1p1aeef4a054a80b5d822ed3dc4b16139d7 X-Msg-Generator: CA X-RootMTR: 20200522101524eucas1p1aeef4a054a80b5d822ed3dc4b16139d7 X-EPHeader: CA CMS-TYPE: 201P X-CMS-RootMailID: 20200522101524eucas1p1aeef4a054a80b5d822ed3dc4b16139d7 References: Sender: linux-samsung-soc-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-samsung-soc@vger.kernel.org Commit 6fe12cdbcfe3 ("i2c: core: support bus regulator controlling in adapter") added generic suspend and resume functions for i2c devices. Those functions unconditionally access an i2c_client structure assigned to the given i2c device. However, there exist i2c devices in the system without a valid i2c_client. Add the needed check before accessing the i2c_client. This fixes the following issue observed on Samsung Exynos4412-based Odroid U3 board: 8<--- cut here --- Unable to handle kernel NULL pointer dereference at virtual address 00000018 pgd = 2aed198a [00000018] *pgd=00000000 Internal error: Oops: 5 [#1] PREEMPT SMP ARM Modules linked in: CPU: 1 PID: 1295 Comm: rtcwake Not tainted 5.7.0-rc6-02700-g4773d1324da6 #739 Hardware name: Samsung Exynos (Flattened Device Tree) PC is at i2c_suspend_late+0x20/0x48 LR is at dpm_run_callback+0xb4/0x3fc pc : [] lr : [] psr: 20000053 ... Process rtcwake (pid: 1295, stack limit = 0x7f1885cf) Stack: (0xec8f3d70 to 0xec8f4000) ... [] (i2c_suspend_late) from [] (dpm_run_callback+0xb4/0x3fc) [] (dpm_run_callback) from [] (__device_suspend_late+0xcc/0x16c) [] (__device_suspend_late) from [] (dpm_suspend_late+0x10c/0x568) [] (dpm_suspend_late) from [] (suspend_devices_and_enter+0x31c/0xc70) [] (suspend_devices_and_enter) from [] (pm_suspend+0x3f8/0x480) [] (pm_suspend) from [] (state_store+0x6c/0xc8) [] (state_store) from [] (kernfs_fop_write+0x10c/0x228) [] (kernfs_fop_write) from [] (__vfs_write+0x30/0x1d0) [] (__vfs_write) from [] (vfs_write+0xa4/0x170) [] (vfs_write) from [] (ksys_write+0x60/0xd8) [] (ksys_write) from [] (ret_fast_syscall+0x0/0x28) Exception stack(0xec8f3fa8 to 0xec8f3ff0) ... ---[ end trace a43afef431782f37 ]--- Fixes: 6fe12cdbcfe3 ("i2c: core: support bus regulator controlling in adapter") Signed-off-by: Marek Szyprowski --- This fixes suspend/resume issue observed on various board with linux-next from 20200521. --- drivers/i2c/i2c-core-base.c | 24 ++++++++++++++++-------- 1 file changed, 16 insertions(+), 8 deletions(-) diff --git a/drivers/i2c/i2c-core-base.c b/drivers/i2c/i2c-core-base.c index 5be24bf8a194..b531f5ad06b2 100644 --- a/drivers/i2c/i2c-core-base.c +++ b/drivers/i2c/i2c-core-base.c @@ -454,11 +454,13 @@ static int i2c_device_remove(struct device *dev) static int i2c_resume_early(struct device *dev) { struct i2c_client *client = i2c_verify_client(dev); - struct i2c_adapter *adap = client->adapter; int err; + if (!client) + return 0; + if (!pm_runtime_status_suspended(&client->dev)) { - err = regulator_enable(adap->bus_regulator); + err = regulator_enable(client->adapter->bus_regulator); if (err) return err; } @@ -469,15 +471,17 @@ static int i2c_resume_early(struct device *dev) static int i2c_suspend_late(struct device *dev) { struct i2c_client *client = i2c_verify_client(dev); - struct i2c_adapter *adap = client->adapter; int err; + if (!client) + return 0; + err = pm_generic_suspend_late(&client->dev); if (err) return err; if (!pm_runtime_status_suspended(&client->dev)) - return regulator_disable(adap->bus_regulator); + return regulator_disable(client->adapter->bus_regulator); return 0; } @@ -487,10 +491,12 @@ static int i2c_suspend_late(struct device *dev) static int i2c_runtime_resume(struct device *dev) { struct i2c_client *client = i2c_verify_client(dev); - struct i2c_adapter *adap = client->adapter; int err; - err = regulator_enable(adap->bus_regulator); + if (!client) + return 0; + + err = regulator_enable(client->adapter->bus_regulator); if (err) return err; @@ -500,14 +506,16 @@ static int i2c_runtime_resume(struct device *dev) static int i2c_runtime_suspend(struct device *dev) { struct i2c_client *client = i2c_verify_client(dev); - struct i2c_adapter *adap = client->adapter; int err; + if (!client) + return 0; + err = pm_generic_runtime_suspend(&client->dev); if (err) return err; - return regulator_disable(adap->bus_regulator); + return regulator_disable(client->adapter->bus_regulator); } #endif