From: Daniel Thompson <daniel.thompson@linaro.org>
To: Lee Jones <lee.jones@linaro.org>
Cc: arnd@arndb.de, broonie@kernel.org, linus.walleij@linaro.org,
linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org, baohua@kernel.org,
stephan@gerhold.net
Subject: Re: [PATCH v2 7/9] mfd: mfd-core: Protect against NULL call-back function pointer
Date: Mon, 21 Oct 2019 13:30:12 +0100 [thread overview]
Message-ID: <20191021123012.qpk7tgyjtwp3wtxv@holly.lan> (raw)
In-Reply-To: <20191021105822.20271-8-lee.jones@linaro.org>
On Mon, Oct 21, 2019 at 11:58:20AM +0100, Lee Jones wrote:
> If a child device calls mfd_cell_{en,dis}able() without an appropriate
> call-back being set, we are likely to encounter a panic. Avoid this
> by adding suitable checking.
>
> Signed-off-by: Lee Jones <lee.jones@linaro.org>
Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org>
> ---
> drivers/mfd/mfd-core.c | 10 ++++++++++
> 1 file changed, 10 insertions(+)
>
> diff --git a/drivers/mfd/mfd-core.c b/drivers/mfd/mfd-core.c
> index 8126665bb2d8..90b43b44a15a 100644
> --- a/drivers/mfd/mfd-core.c
> +++ b/drivers/mfd/mfd-core.c
> @@ -28,6 +28,11 @@ int mfd_cell_enable(struct platform_device *pdev)
> const struct mfd_cell *cell = mfd_get_cell(pdev);
> int err = 0;
>
> + if (!cell->enable) {
> + dev_dbg(&pdev->dev, "No .enable() call-back registered\n");
> + return 0;
> + }
> +
> /* only call enable hook if the cell wasn't previously enabled */
> if (atomic_inc_return(cell->usage_count) == 1)
> err = cell->enable(pdev);
> @@ -45,6 +50,11 @@ int mfd_cell_disable(struct platform_device *pdev)
> const struct mfd_cell *cell = mfd_get_cell(pdev);
> int err = 0;
>
> + if (!cell->enable) {
> + dev_dbg(&pdev->dev, "No .disable() call-back registered\n");
> + return 0;
> + }
> +
> /* only disable if no other clients are using it */
> if (atomic_dec_return(cell->usage_count) == 0)
> err = cell->disable(pdev);
> --
> 2.17.1
>
next prev parent reply other threads:[~2019-10-21 12:30 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-10-21 10:58 [PATCH v2 0/9] Simplify MFD Core Lee Jones
2019-10-21 10:58 ` [PATCH v2 1/9] mfd: cs5535-mfd: Use PLATFORM_DEVID_* defines and tidy error message Lee Jones
2019-10-21 11:15 ` Daniel Thompson
2019-10-21 11:33 ` Lee Jones
2019-10-21 11:35 ` Lee Jones
2019-10-21 10:58 ` [PATCH v2 2/9] mfd: cs5535-mfd: Remove mfd_cell->id hack Lee Jones
2019-10-21 11:11 ` Daniel Thompson
2019-10-21 11:46 ` Lee Jones
2019-10-21 10:58 ` [PATCH v2 3/9] mfd: cs5535-mfd: Request shared IO regions centrally Lee Jones
2019-10-21 12:26 ` Daniel Thompson
2019-10-21 12:46 ` Lee Jones
2019-10-21 10:58 ` [PATCH v2 4/9] mfd: cs5535-mfd: Register clients using their own dedicated MFD cell entries Lee Jones
2019-10-21 12:29 ` Daniel Thompson
2019-10-21 13:21 ` Lee Jones
2019-10-21 10:58 ` [PATCH v2 5/9] mfd: mfd-core: Remove mfd_clone_cell() Lee Jones
2019-10-21 12:29 ` Daniel Thompson
2019-10-21 10:58 ` [PATCH v2 6/9] x86: olpc: Remove invocation of MFD's .enable()/.disable() call-backs Lee Jones
2019-10-21 12:17 ` Daniel Thompson
2019-10-21 10:58 ` [PATCH v2 7/9] mfd: mfd-core: Protect against NULL call-back function pointer Lee Jones
2019-10-21 12:30 ` Daniel Thompson [this message]
2019-10-21 12:32 ` Daniel Thompson
2019-10-21 12:40 ` Lee Jones
2019-10-21 10:58 ` [PATCH v2 8/9] mfd: mfd-core: Remove usage counting for .{en,dis}able() call-backs Lee Jones
2019-10-21 12:33 ` Daniel Thompson
2019-10-21 10:58 ` [PATCH v2 9/9] mfd: mfd-core: Move pdev->mfd_cell creation back into mfd_add_device() Lee Jones
2019-10-21 12:45 ` Daniel Thompson
2019-10-21 11:29 ` [PATCH v2 0/9] Simplify MFD Core Arnd Bergmann
2019-10-21 11:39 ` Lee Jones
2019-10-21 11:44 ` Lubomir Rintel
2019-10-21 11:53 ` Lee Jones
2019-10-21 12:21 ` Lubomir Rintel
2019-10-21 13:01 ` Lee Jones
2019-11-01 9:07 ` Lee Jones
2019-11-01 15:01 ` Lubomir Rintel
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