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authorParag Warudkar <pwarudkar@aol.com>2007-05-08 03:31:09 -0400
committerLinus Torvalds <torvalds@woody.linux-foundation.org>2007-05-08 14:15:13 -0400
commit8e39c933b1b7df501dbb68879fb1640e277b8a5c (patch)
tree870bb5506fb670d0e44c00a7d330ee064239298b /drivers/char/tpm
parent53ab97a1c1536015d4d6d900363ea96fece5ed97 (diff)
tpm: fix sleep-in-spinlock
flush_scheduled_work() can sleep, and we're calling it under spinlock. AFAICS, moving flush_scheduled_work before spin_lock() should not cause any problems. Reason being - The only thing that can race against tpm_release is tpm_open (tpm_release is called when last reference to the file is closed and only thing that can happen after that is tpm_open??) and tpm_open acquires driver_lock and more over it bails out with EBUSY if chip->num_opens is greater than 0. I also moved chip->num_pending-- to after deleting timer and setting data pending as it looks more correct for the paranoid although it probably doesn't matter as it is guarded by driver_lock. None the less this change should not cause problems. While I was at it I noticed a missing NULL check in tpm_register_hardware which is fixed with this patch as well. Signed-off-by: Parag Warudkar <parag.warudkar@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'drivers/char/tpm')
-rw-r--r--drivers/char/tpm/tpm.c12
1 files changed, 8 insertions, 4 deletions
diff --git a/drivers/char/tpm/tpm.c b/drivers/char/tpm/tpm.c
index e5a254a434f8..ef991cd8c024 100644
--- a/drivers/char/tpm/tpm.c
+++ b/drivers/char/tpm/tpm.c
@@ -942,12 +942,12 @@ int tpm_release(struct inode *inode, struct file *file)
942{ 942{
943 struct tpm_chip *chip = file->private_data; 943 struct tpm_chip *chip = file->private_data;
944 944
945 flush_scheduled_work();
945 spin_lock(&driver_lock); 946 spin_lock(&driver_lock);
946 file->private_data = NULL; 947 file->private_data = NULL;
947 chip->num_opens--;
948 del_singleshot_timer_sync(&chip->user_read_timer); 948 del_singleshot_timer_sync(&chip->user_read_timer);
949 flush_scheduled_work();
950 atomic_set(&chip->data_pending, 0); 949 atomic_set(&chip->data_pending, 0);
950 chip->num_opens--;
951 put_device(chip->dev); 951 put_device(chip->dev);
952 kfree(chip->data_buffer); 952 kfree(chip->data_buffer);
953 spin_unlock(&driver_lock); 953 spin_unlock(&driver_lock);
@@ -1097,8 +1097,13 @@ struct tpm_chip *tpm_register_hardware(struct device *dev, const struct tpm_vend
1097 1097
1098 /* Driver specific per-device data */ 1098 /* Driver specific per-device data */
1099 chip = kzalloc(sizeof(*chip), GFP_KERNEL); 1099 chip = kzalloc(sizeof(*chip), GFP_KERNEL);
1100 if (chip == NULL) 1100 devname = kmalloc(DEVNAME_SIZE, GFP_KERNEL);
1101
1102 if (chip == NULL || devname == NULL) {
1103 kfree(chip);
1104 kfree(devname);
1101 return NULL; 1105 return NULL;
1106 }
1102 1107
1103 init_MUTEX(&chip->buffer_mutex); 1108 init_MUTEX(&chip->buffer_mutex);
1104 init_MUTEX(&chip->tpm_mutex); 1109 init_MUTEX(&chip->tpm_mutex);
@@ -1124,7 +1129,6 @@ struct tpm_chip *tpm_register_hardware(struct device *dev, const struct tpm_vend
1124 1129
1125 set_bit(chip->dev_num, dev_mask); 1130 set_bit(chip->dev_num, dev_mask);
1126 1131
1127 devname = kmalloc(DEVNAME_SIZE, GFP_KERNEL);
1128 scnprintf(devname, DEVNAME_SIZE, "%s%d", "tpm", chip->dev_num); 1132 scnprintf(devname, DEVNAME_SIZE, "%s%d", "tpm", chip->dev_num);
1129 chip->vendor.miscdev.name = devname; 1133 chip->vendor.miscdev.name = devname;
1130 1134