From: Greg KH <gregkh@linuxfoundation.org> To: Christophe JAILLET <christophe.jaillet@wanadoo.fr> Cc: jk@ozlabs.org, joel@jms.id.au, alistair@popple.id.au, eajames@linux.ibm.com, andrew@aj.id.au, linux-fsi@lists.ozlabs.org, linux-arm-kernel@lists.infradead.org, linux-aspeed@lists.ozlabs.org, linux-kernel@vger.kernel.org, kernel-janitors@vger.kernel.org Subject: Re: [PATCH] fsi: Aspeed: Fix a potential double free Date: Mon, 27 Dec 2021 07:29:07 +0100 [thread overview] Message-ID: <YcldM9sgYdjMYMtH@kroah.com> (raw) In-Reply-To: <2cafa0607ca171ebd00ac6c7e073b46808e24f00.1640537669.git.christophe.jaillet@wanadoo.fr> On Sun, Dec 26, 2021 at 05:56:02PM +0100, Christophe JAILLET wrote: > 'aspeed' is a devm_alloc'ed, so there is no need to free it explicitly or > there will be a double free(). A struct device can never be devm_alloced for obvious reasons. Perhaps that is the real problem here? > Remove the 'release' function that is wrong and unneeded. > > Fixes: 606397d67f41 ("fsi: Add ast2600 master driver") > Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr> > --- > This patch is completely theoretical. It looks good to me, but there is a > little too much indirections for me. I'm also not that familiar with > fixing issue related to 'release' function... > > ... So review with care :) > --- > drivers/fsi/fsi-master-aspeed.c | 9 --------- > 1 file changed, 9 deletions(-) > > diff --git a/drivers/fsi/fsi-master-aspeed.c b/drivers/fsi/fsi-master-aspeed.c > index 8606e55c1721..4a745ccb60cf 100644 > --- a/drivers/fsi/fsi-master-aspeed.c > +++ b/drivers/fsi/fsi-master-aspeed.c > @@ -373,14 +373,6 @@ static int aspeed_master_break(struct fsi_master *master, int link) > return aspeed_master_write(master, link, 0, addr, &cmd, 4); > } > > -static void aspeed_master_release(struct device *dev) > -{ > - struct fsi_master_aspeed *aspeed = > - to_fsi_master_aspeed(dev_to_fsi_master(dev)); > - > - kfree(aspeed); > -} > - > /* mmode encoders */ > static inline u32 fsi_mmode_crs0(u32 x) > { > @@ -603,7 +595,6 @@ static int fsi_master_aspeed_probe(struct platform_device *pdev) > dev_info(&pdev->dev, "hub version %08x (%d links)\n", reg, links); > > aspeed->master.dev.parent = &pdev->dev; > - aspeed->master.dev.release = aspeed_master_release; Odd, then what deletes this device structure when the release function wants to be called? You should have gotten a big warning from the kernel when removing the device from the system at runtime, did you test this somehow? This does not look correct at all. greg k-h
WARNING: multiple messages have this Message-ID (diff)
From: Greg KH <gregkh@linuxfoundation.org> To: Christophe JAILLET <christophe.jaillet@wanadoo.fr> Cc: jk@ozlabs.org, joel@jms.id.au, alistair@popple.id.au, eajames@linux.ibm.com, andrew@aj.id.au, linux-fsi@lists.ozlabs.org, linux-arm-kernel@lists.infradead.org, linux-aspeed@lists.ozlabs.org, linux-kernel@vger.kernel.org, kernel-janitors@vger.kernel.org Subject: Re: [PATCH] fsi: Aspeed: Fix a potential double free Date: Mon, 27 Dec 2021 07:29:07 +0100 [thread overview] Message-ID: <YcldM9sgYdjMYMtH@kroah.com> (raw) In-Reply-To: <2cafa0607ca171ebd00ac6c7e073b46808e24f00.1640537669.git.christophe.jaillet@wanadoo.fr> On Sun, Dec 26, 2021 at 05:56:02PM +0100, Christophe JAILLET wrote: > 'aspeed' is a devm_alloc'ed, so there is no need to free it explicitly or > there will be a double free(). A struct device can never be devm_alloced for obvious reasons. Perhaps that is the real problem here? > Remove the 'release' function that is wrong and unneeded. > > Fixes: 606397d67f41 ("fsi: Add ast2600 master driver") > Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr> > --- > This patch is completely theoretical. It looks good to me, but there is a > little too much indirections for me. I'm also not that familiar with > fixing issue related to 'release' function... > > ... So review with care :) > --- > drivers/fsi/fsi-master-aspeed.c | 9 --------- > 1 file changed, 9 deletions(-) > > diff --git a/drivers/fsi/fsi-master-aspeed.c b/drivers/fsi/fsi-master-aspeed.c > index 8606e55c1721..4a745ccb60cf 100644 > --- a/drivers/fsi/fsi-master-aspeed.c > +++ b/drivers/fsi/fsi-master-aspeed.c > @@ -373,14 +373,6 @@ static int aspeed_master_break(struct fsi_master *master, int link) > return aspeed_master_write(master, link, 0, addr, &cmd, 4); > } > > -static void aspeed_master_release(struct device *dev) > -{ > - struct fsi_master_aspeed *aspeed = > - to_fsi_master_aspeed(dev_to_fsi_master(dev)); > - > - kfree(aspeed); > -} > - > /* mmode encoders */ > static inline u32 fsi_mmode_crs0(u32 x) > { > @@ -603,7 +595,6 @@ static int fsi_master_aspeed_probe(struct platform_device *pdev) > dev_info(&pdev->dev, "hub version %08x (%d links)\n", reg, links); > > aspeed->master.dev.parent = &pdev->dev; > - aspeed->master.dev.release = aspeed_master_release; Odd, then what deletes this device structure when the release function wants to be called? You should have gotten a big warning from the kernel when removing the device from the system at runtime, did you test this somehow? This does not look correct at all. greg k-h _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
next prev parent reply other threads:[~2021-12-27 6:29 UTC|newest] Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top 2021-12-26 16:56 [PATCH] fsi: Aspeed: Fix a potential double free Christophe JAILLET 2021-12-26 16:56 ` Christophe JAILLET 2021-12-27 6:29 ` Greg KH [this message] 2021-12-27 6:29 ` Greg KH 2021-12-27 7:48 ` Christophe JAILLET 2021-12-27 7:48 ` Christophe JAILLET 2022-01-06 8:14 ` Dan Carpenter 2022-01-06 8:14 ` Dan Carpenter 2022-01-06 17:25 ` Guenter Roeck 2022-01-06 17:25 ` Guenter Roeck 2022-01-06 18:35 ` Christophe JAILLET 2022-01-06 18:35 ` Christophe JAILLET 2022-01-07 1:35 ` Guenter Roeck 2022-01-07 1:35 ` Guenter Roeck
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