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author | Mark A. Greer <mgreer@animalcreek.com> | 2014-07-02 20:03:49 +0400 |
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committer | Samuel Ortiz <sameo@linux.intel.com> | 2014-07-21 02:45:11 +0400 |
commit | 0529a7adf3421acf251355444a012073abaffebc (patch) | |
tree | 6aee9b69ddc4bb59f559197575eba606f532334f /kernel/acct.c | |
parent | 4b4dbca5e49eea2567d0da777fea2c86e7b89622 (diff) | |
download | linux-0529a7adf3421acf251355444a012073abaffebc.tar.xz |
NFC: digital: Clear poll_tech_count before activating target
Currently, digital_target_found() has a race between
the events started by calling nfc_targets_found()
(which ultimately expect ddev->poll_tech_count to be
zero) and setting ddev->poll_tech_count to zero after
the call to nfc_targets_found(). When the race is
"lost" (i.e., ddev->poll_tech_count is found to not
be zero by the events started by nfc_targets_found()),
an error message is printed and the target is not found.
A similar race exists when digital_tg_recv_atr_req()
calls nfc_tm_activated().
Fix this by first saving the current value of
ddev->poll_tech_count and then clearing it before
calling nfc_targets_found()/nfc_tm_activated().
Clearing ddev->poll_tech_count before calling
nfc_targets_found()/nfc_tm_activated() eliminates
the race. Saving the value is required so it can be
restored when nfc_targets_found()/nfc_tm_activated()
fails and polling needs to continue.
Acked-by: Thierry Escande <thierry.escande@linux.intel.com>
Signed-off-by: Mark A. Greer <mgreer@animalcreek.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
Diffstat (limited to 'kernel/acct.c')
0 files changed, 0 insertions, 0 deletions