Red Hat Bugzilla – Bug 194413
Scheduler keeps process in runnable state (instead of interruptible)
Last modified: 2008-01-19 23:36:52 EST
Description of problem:
A process can consume 99.9% of the CPU, when it ought to be blocked;
it stays in state 0.
Version-Release number of selected component (if applicable):
2.6.12-1.1456_FC4 (from "uname -r")
This was fairly easy to reproduce, once I had rebuilt crash. This
has occured in other ways too.
I rebuilt crash(8) and then did
crash> foreach bt
and hit the <spacebar> key a few times in rapid succession and
then stopped. This left me in a state somewhat equivalent to
more(1). A kernel stack trace (from a second instance of "crash")
PID: 8993 TASK: ffff810058d247c0 CPU: 0 COMMAND: "crash"
#0 [ffff81002b86fd38] schedule at ffffffff8032d36e
#1 [ffff81002b86fe00] pipe_wait at ffffffff8018a16d
#2 [ffff81002b86fe50] pipe_writev at ffffffff8018b19c
#3 [ffff81002b86fef0] pipe_write at ffffffff8018b25f
#4 [ffff81002b86ff10] vfs_write at ffffffff8017efc0
#5 [ffff81002b86ff40] sys_write at ffffffff8017f4b3
#6 [ffff81002b86ff80] tracesys at ffffffff8010e89e
RIP: 0000003ecb6bc090 RSP: 00007fffffc1d238 RFLAGS: 00000246
RAX: ffffffffffffffda RBX: ffffffff8010e89e RCX: ffffffffffffffff
RDX: 0000000000000048 RSI: 00007fffffc1d2b0 RDI: 000000000000000b
RBP: 0000000000000048 R8: 00002aaaaaae19e0 R9: 0000003ecb70ba80
R10: 00007fffffc1fcf0 R11: 0000000000000246 R12: 00007fffffc1d2b0
R13: 00000000018e2990 R14: 0000000000000048 R15: 0000000000000048
ORIG_RAX: 0000000000000001 CS: 0033 SS: 002b
Printing out the "state" field of the kernel's "struct task_struct"
for the crash process shows that it equals 0 (i.e. "runnable").
(Both of these obtained, via crash(8) utility.)
When the (above) problem does not occur, printing that same "state" field
shows 1 ("interruptible").
Steps to Reproduce:
1. (See above)
crash process which should be blocked, waiting for keyboard input,
remains runnable and therefore sucks up all the idle CPU time.
crash process should be blocked, waiting for keyboard input.
[This comment added as part of a mass-update to all open FC4 kernel bugs]
FC4 has now transitioned to the Fedora legacy project, which will continue to
release security related updates for the kernel. As this bug is not security
related, it is unlikely to be fixed in an update for FC4, and has been migrated
Please retest with Fedora Core 5.
A new kernel update has been released (Version: 2.6.18-1.2200.fc5)
based upon a new upstream kernel release.
Please retest against this new kernel, as a large number of patches
go into each upstream release, possibly including changes that
may address this problem.
This bug has been placed in NEEDINFO state.
Due to the large volume of inactive bugs in bugzilla, if this bug is
still in this state in two weeks time, it will be closed.
Should this bug still be relevant after this period, the reporter
can reopen the bug at any time. Any other users on the Cc: list
of this bug can request that the bug be reopened by adding a
comment to the bug.
In the last few updates, some users upgrading from FC4->FC5
have reported that installing a kernel update has left their
systems unbootable. If you have been affected by this problem
please check you only have one version of device-mapper & lvm2
installed. See bug 207474 for further details.
If this bug is a problem preventing you from installing the
release this version is filed against, please see bug 169613.
If this bug has been fixed, but you are now experiencing a different
problem, please file a separate bug for the new problem.
(this is a mass-close to kernel bugs in NEEDINFO state)
As indicated previously there has been no update on the progress of this bug
therefore I am closing it as INSUFFICIENT_DATA. Please re-open if the issue
still occurs for you and I will try to assist in its resolution. Thank you for
taking the time to report the initial bug.
If you believe that this bug was closed in error, please feel free to reopen