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[104.57.184.186]) by smtp.gmail.com with ESMTPSA id r23sm1275221otu.54.2021.09.23.07.07.24 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 23 Sep 2021 07:07:24 -0700 (PDT) Date: Thu, 23 Sep 2021 07:08:05 -0700 From: Bjorn Andersson To: Vladimir Zapolskiy Cc: Andy Gross , Kishon Vijay Abraham I , Vinod Koul , Vivek Gautam , linux-arm-msm@vger.kernel.org, linux-phy@lists.infradead.org Subject: Re: [PATCH v2] phy: qcom-qusb2: Fix a memory leak on probe Message-ID: References: <20210922233548.2150244-1-vladimir.zapolskiy@linaro.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210922233548.2150244-1-vladimir.zapolskiy@linaro.org> Precedence: bulk List-ID: X-Mailing-List: linux-arm-msm@vger.kernel.org On Wed 22 Sep 16:35 PDT 2021, Vladimir Zapolskiy wrote: > On success nvmem_cell_read() returns a pointer to a dynamically allocated > buffer, and therefore it shall be freed after usage. > > The issue is reported by kmemleak: > > # cat /sys/kernel/debug/kmemleak > unreferenced object 0xffff3b3803e4b280 (size 128): > comm "kworker/u16:1", pid 107, jiffies 4294892861 (age 94.120s) > hex dump (first 32 bytes): > 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ > 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ > backtrace: > [<000000007739afdc>] __kmalloc+0x27c/0x41c > [<0000000071c0fbf8>] nvmem_cell_read+0x40/0xe0 > [<00000000e803ef1f>] qusb2_phy_init+0x258/0x5bc > [<00000000fc81fcfa>] phy_init+0x70/0x110 > [<00000000e3d48a57>] dwc3_core_soft_reset+0x4c/0x234 > [<0000000027d1dbd4>] dwc3_core_init+0x68/0x990 > [<000000001965faf9>] dwc3_probe+0x4f4/0x730 > [<000000002f7617ca>] platform_probe+0x74/0xf0 > [<00000000a2576cac>] really_probe+0xc4/0x470 > [<00000000bc77f2c5>] __driver_probe_device+0x11c/0x190 > [<00000000130db71f>] driver_probe_device+0x48/0x110 > [<0000000019f36c2b>] __device_attach_driver+0xa4/0x140 > [<00000000e5812ff7>] bus_for_each_drv+0x84/0xe0 > [<00000000f4bac574>] __device_attach+0xe4/0x1c0 > [<00000000d3beb631>] device_initial_probe+0x20/0x30 > [<000000008019b9db>] bus_probe_device+0xa4/0xb0 > > Fixes: ca04d9d3e1b1 ("phy: qcom-qusb2: New driver for QUSB2 PHY on Qcom chips") > Signed-off-by: Vladimir Zapolskiy > --- > Changes from v1 to v2: > * fixed a memory leak in case of reading a zero value and return, > * corrected the fixed commit, the memory leak is present before a rename. > > drivers/phy/qualcomm/phy-qcom-qusb2.c | 16 ++++++++++------ > 1 file changed, 10 insertions(+), 6 deletions(-) > > diff --git a/drivers/phy/qualcomm/phy-qcom-qusb2.c b/drivers/phy/qualcomm/phy-qcom-qusb2.c > index 3c1d3b71c825..f1d97fbd1331 100644 > --- a/drivers/phy/qualcomm/phy-qcom-qusb2.c > +++ b/drivers/phy/qualcomm/phy-qcom-qusb2.c > @@ -561,7 +561,7 @@ static void qusb2_phy_set_tune2_param(struct qusb2_phy *qphy) > { > struct device *dev = &qphy->phy->dev; > const struct qusb2_phy_cfg *cfg = qphy->cfg; > - u8 *val; > + u8 *val, hstx_trim; > > /* efuse register is optional */ > if (!qphy->cell) > @@ -575,7 +575,13 @@ static void qusb2_phy_set_tune2_param(struct qusb2_phy *qphy) > * set while configuring the phy. > */ > val = nvmem_cell_read(qphy->cell, NULL); > - if (IS_ERR(val) || !val[0]) { > + if (IS_ERR(val)) { > + dev_dbg(dev, "failed to read a valid hs-tx trim value\n"); > + return; > + } > + hstx_trim = val[0]; > + kfree(val); I don't see any additional value added by the introduction of "hstx_trim", compared to v1. However, it certainly makes sense if you change this to: ret = nvmem_cell_read_u8(qphy->cell, NULL, &hstx_trim); if (ret < 0 || !hstx_trim) { dev_dbg(dev, "failed to read a valid hs-tx trim value\n"); return; } In which case you don't need the kfree(), and you can drop "val"... Regards, Bjorn > + if (!hstx_trim) { > dev_dbg(dev, "failed to read a valid hs-tx trim value\n"); > return; > } > @@ -583,12 +589,10 @@ static void qusb2_phy_set_tune2_param(struct qusb2_phy *qphy) > /* Fused TUNE1/2 value is the higher nibble only */ > if (cfg->update_tune1_with_efuse) > qusb2_write_mask(qphy->base, cfg->regs[QUSB2PHY_PORT_TUNE1], > - val[0] << HSTX_TRIM_SHIFT, > - HSTX_TRIM_MASK); > + hstx_trim << HSTX_TRIM_SHIFT, HSTX_TRIM_MASK); > else > qusb2_write_mask(qphy->base, cfg->regs[QUSB2PHY_PORT_TUNE2], > - val[0] << HSTX_TRIM_SHIFT, > - HSTX_TRIM_MASK); > + hstx_trim << HSTX_TRIM_SHIFT, HSTX_TRIM_MASK); > } > > static int qusb2_phy_set_mode(struct phy *phy, > -- > 2.33.0 >