Messages in this thread Patch in this message | | | Date | Mon, 28 Apr 2008 03:01:56 -0400 | From | Dan Noe <> | Subject | Re: NULL dereference OOPS on SysRq-w |
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Dave Young wrote: > [snip] > > I have a fix for the NULL pointer reference BUG, tested on my pc. > --- > > "m" will be NULL if seq_printf & seq_puts is called from sched_debug_show > Use SEQ_* macros to fix it > > Signed-off-by: Dave Young <hidave.darkstar@gmail.com>
There is actually already a patch out for this which simply hasn't made it upstream yet - Mike Galbraith emailed me with it and it indeed fixes the problem. I hadn't realized his email didn't go to lkml.. otherwise I would have echoed that here to avoid wasting people's time. My apologies.
Cheers, Dan
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Here is his message:
From: efault@gmx.de
Peter's fix didn't make it up-stream.
Subject: sched: fix oops
sched_debug uses SEQ_printf to use printk when the seqfile 'm' is NULL. Instead of doing that here too; choose to not output the weight tree to cut back on output.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> --- diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c index 89fa32b..353a481 100644 --- a/kernel/sched_fair.c +++ b/kernel/sched_fair.c @@ -1643,8 +1643,10 @@ static void print_cfs_stats(struct seq_file *m, int cpu) for_each_leaf_cfs_rq(cpu_rq(cpu), cfs_rq) print_cfs_rq(m, cpu, cfs_rq);
- seq_printf(m, "\nWeight tree:\n"); - print_cfs_rq_tasks(m, &cpu_rq(cpu)->cfs, 1); + if (m) { + seq_printf(m, "\nWeight tree:\n"); + print_cfs_rq_tasks(m, &cpu_rq(cpu)->cfs, 1); + } rcu_read_unlock(); } #endif
-- /--------------- - - - - - - | Dan Noe | http://isomerica.net/~dpn/
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