lkml.org 
[lkml]   [2005]   [Jun]   [23]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Date
From
SubjectRe: 2.6.12-mm1: BUG() in fd_install, RCU related?
On Thu, Jun 23, 2005 at 01:50:11PM +0200, syrius.ml@no-log.org wrote:
> Dipankar Sarma <dipankar@in.ibm.com> writes:
>
> > Some things are common - always with fcntl() or fcntl64() and with
> > a daemon. Does your box come up at all ? If so, can you get me an
> > strace on the process that triggers this ? If I can narrow it
> > down to a small testcase, it would be a lot easier. Also, does
> > switching off CONFIG_PREEMPT fix this problem ?
>
> I haven't read about this thread. I hope u'll find a way to reproduce
> it. here debian/sid i386 (.config sent in an earlier message), it 100%
> reproducible when restarting bind9. (it also happens on its own on
> different occasion)
>
>
> then i restart the daemon:
>
> end of a strace -f /etc/init.d/bind9 start
> 6541 rt_sigaction(SIGPIPE, {0xb7ca2a70, [], 0}, {SIG_IGN}, 8) = 0
> 6541 send(3, "<30>Jun 23 00:51:35 named[6540]:"..., 82, 0) = 82
> 6541 rt_sigaction(SIGPIPE, {SIG_IGN}, NULL, 8) = 0
> 6541 socket(PF_INET, SOCK_DGRAM, IPPROTO_UDP) = 10
> 6541 fcntl64(10, F_DUPFD, 20) = 32
> 6541 close(10) = 0
> 6541 fcntl64(32, F_GETFL) = 0x2 (flags O_RDWR)
> 6541 fcntl64(32, F_SETFL, O_RDWR|O_NONBLOCK) = 0
> 6541 setsockopt(32, SOL_SOCKET, SO_TIMESTAMP, [1], 4) = 0
> 6541 setsockopt(32, SOL_SOCKET, SO_REUSEADDR, [1], 4) = 0
> 6541 bind(32, {sa_family=AF_INET, sin_port=htons(53),
> sin_addr=inet_addr("172.16.254.1")}, 16) = 0
> 6541 socket(PF_INET, SOCK_STREAM, IPPROTO_TCP) = 10
> 6541 fcntl64(10, F_DUPFD, 20

Aha, this has been extremely helpful. Could you all please try the
following (untested) patch ? This should fix the problem, or
atleast one problem that I can see.

Thanks
Dipankar


locate_fd() may expand fdtable, so the fdtable pointer must be
reloaded after locate_fd().

Signed-of-by: Dipankar Sarma <dipankar@in.ibm.com>
---


fs/fcntl.c | 3 ++-
1 files changed, 2 insertions(+), 1 deletion(-)

diff -puN fs/fcntl.c~fix-dupfd-reacquire-fdt fs/fcntl.c
--- linux-2.6.12-mm1-fix/fs/fcntl.c~fix-dupfd-reacquire-fdt 2005-06-25 14:56:58.000000000 +0530
+++ linux-2.6.12-mm1-fix-dipankar/fs/fcntl.c 2005-06-25 14:58:26.000000000 +0530
@@ -118,9 +118,10 @@ static int dupfd(struct file *file, unsi
int fd;

spin_lock(&files->file_lock);
- fdt = files_fdtable(files);
fd = locate_fd(files, file, start);
if (fd >= 0) {
+ /* locate_fd() may have expanded fdtable, load the ptr */
+ fdt = files_fdtable(files);
FD_SET(fd, fdt->open_fds);
FD_CLR(fd, fdt->close_on_exec);
spin_unlock(&files->file_lock);
_
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/

\
 
 \ /
  Last update: 2005-06-23 21:17    [W:0.056 / U:0.488 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site