evie/android_kernel_oneplus_msm8998
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mmc: core: claim mmc host while enabling clock scaling from userspace

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A race condition can occur while enabling clock scaling and removal
of the card. If the card is removed just after the host->card check
is successful then there could be NULL pointer dereference later.
Claim mmc host before card availability check to avoid this race
condition.

Change-Id: I6339cad5857732ec6b66280940cd6b8b7ed30614
Signed-off-by: Sujit Reddy Thumma <sthumma@codeaurora.org>
This commit is contained in:
Sujit Reddy Thumma 2012-12-12 09:16:58 +05:30 • committed by Subhash Jadavani
parent d98ae31eee
commit 7a2c9513a1
1 changed files with 8 additions and 2 deletions
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10
drivers/mmc/core/host.c
View file

@ -633,7 +633,11 @@ static ssize_t store_enable(struct device *dev,
unsigned long value, freq;
int retval = -EINVAL;
if (!host || !host->card || kstrtoul(buf, 0, &value))
if (!host)
goto out;
mmc_claim_host(host);
if (!host->card || kstrtoul(buf, 0, &value))
goto err;
if (value && !mmc_can_scale_clk(host)) {
@ -659,8 +663,10 @@ static ssize_t store_enable(struct device *dev,
}
host->clk_scaling.initialized = false;
}
return count;
retval = count;
err:
mmc_release_host(host);
out:
return retval;
}