]> git.proxmox.com Git - mirror_ubuntu-eoan-kernel.git/commit
tpm: fix an invalid condition in tpm_common_poll
authorTadeusz Struk <tadeusz.struk@intel.com>
Wed, 27 Mar 2019 18:32:38 +0000 (11:32 -0700)
committerJames Morris <james.morris@microsoft.com>
Mon, 8 Apr 2019 22:58:53 +0000 (15:58 -0700)
commit7110629263469b4664d00b38ef80a656eddf3637
tree37d9040e8ac9e3fcd3644d85a2960172ee510413
parente891db1a18bf11e02533ec2386b796cfd8d60666
tpm: fix an invalid condition in tpm_common_poll

The poll condition should only check response_length,
because reads should only be issued if there is data to read.
The response_read flag only prevents double writes.
The problem was that the write set the response_read to false,
enqued a tpm job, and returned. Then application called poll
which checked the response_read flag and returned EPOLLIN.
Then the application called read, but got nothing.
After all that the async_work kicked in.
Added also mutex_lock around the poll check to prevent
other possible race conditions.

Fixes: 9488585b21bef0df12 ("tpm: add support for partial reads")
Reported-by: Mantas Mikulėnas <grawity@gmail.com>
Tested-by: Mantas Mikulėnas <grawity@gmail.com>
Signed-off-by: Tadeusz Struk <tadeusz.struk@intel.com>
Reviewed-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Signed-off-by: James Morris <james.morris@microsoft.com>
drivers/char/tpm/tpm-dev-common.c