[lkml]   [2006]   [Jul]   [28]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
Patch in this message
Subject[KJ] audit return code handling for kernel_thread [8/11]
Audit/Cleanup of kernel_thread calls, specifically checking of return codes.
Problems seemed to fall into 3 main categories:

1) callers of kernel_thread were inconsistent about meaning of a zero return
code. Some callers considered a zero return code to mean success, others took
it to mean failure. a zero return code, while not actually possible in the
current implementation, should be considered a success (pid 0 is/should be
valid). fixed all callers to treat zero return as success

2) caller of kernel_thread saved return code of kernel_thread for later use
without ever checking its value. Callers who did this tended to assume a
non-zero return was success, and would often wait for a completion queue to be
woken up, implying that an error (negative return code) from kernel_thread could
lead to deadlock. Repaired by checking return code at call time, and setting
saved return code to zero in the event of an error.

3) callers of kernel_thread never bothered to check the return code at all.
This can lead to seemingly unrelated errors later in execution. Fixed by
checking return code at call time and printing a warning message on failure.


Signed-off-by: Neil Horman <>

drivers/ieee1394/nodemgr.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
--- a/drivers/ieee1394/nodemgr.c
+++ b/drivers/ieee1394/nodemgr.c
@@ -426,7 +426,8 @@ static ssize_t fw_set_rescan(struct bus_
* something stupid and spawn this a lot of times, but that's
* root's fault. */
if (state == 1)
- kernel_thread(nodemgr_rescan_bus_thread, NULL, CLONE_KERNEL);
+ if (kernel_thread(nodemgr_rescan_bus_thread, NULL, CLONE_KERNEL) < 0)
+ printk(KERN_WARNING "Could not start 1394 bus rescan thread\n");

return count;
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to
More majordomo info at
Please read the FAQ at
 \ /
  Last update: 2006-07-28 22:13    [W:0.038 / U:1.600 seconds]
©2003-2018 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site