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authorJason Gunthorpe <jgunthorpe@obsidianresearch.com>2017-01-23 17:06:08 -0700
committerJarkko Sakkinen <jarkko.sakkinen@linux.intel.com>2017-02-03 22:03:14 +0200
commitfa2825da6f5d6d45122bd990958970a175fb1aef (patch)
treecd28b41d6ee01e2482d54715076a24040b1baa6d /drivers/char
parent1d1915532b3fb0d08aed8b2d8af1c6ea40846782 (diff)
downloadlinux-fa2825da6f5d6d45122bd990958970a175fb1aef.tar.bz2
tpm: Begin the process to deprecate user_read_timer
For a long time the cdev read/write interface had this strange idea that userspace had to read the result within 60 seconds otherwise it is discarded. Perhaps this made sense under some older locking regime, but in the modern kernel it is not required and is just dangerous. Since something may be relying on this, double the timeout and print a warning. We can remove the code in a few years, but this should be enough to prevent new users. Suggested-by: James Bottomley <James.Bottomley@HansenPartnership.com> Signed-off-by: Jason Gunthorpe <jgunthorpe@obsidianresearch.com> Reviewed-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com> Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Diffstat (limited to 'drivers/char')
-rw-r--r--drivers/char/tpm/tpm-dev.c5
1 files changed, 4 insertions, 1 deletions
diff --git a/drivers/char/tpm/tpm-dev.c b/drivers/char/tpm/tpm-dev.c
index 912ad30be585..02a8850d3a69 100644
--- a/drivers/char/tpm/tpm-dev.c
+++ b/drivers/char/tpm/tpm-dev.c
@@ -38,6 +38,9 @@ static void user_reader_timeout(unsigned long ptr)
{
struct file_priv *priv = (struct file_priv *)ptr;
+ pr_warn("TPM user space timeout is deprecated (pid=%d)\n",
+ task_tgid_nr(current));
+
schedule_work(&priv->work);
}
@@ -157,7 +160,7 @@ static ssize_t tpm_write(struct file *file, const char __user *buf,
mutex_unlock(&priv->buffer_mutex);
/* Set a timeout by which the reader must come claim the result */
- mod_timer(&priv->user_read_timer, jiffies + (60 * HZ));
+ mod_timer(&priv->user_read_timer, jiffies + (120 * HZ));
return in_size;
}