Messages in this thread | | | Date | Mon, 9 Oct 2006 00:44:40 +0200 | From | Willy Tarreau <> | Subject | Re: 2.4.x: i386/x86_64 bitops clobberings |
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Hi Jan,
On Sun, Oct 08, 2006 at 11:42:07PM +0200, Jan Kiszka wrote: > Hi, > > after going through debugging hell with some out-of-tree code, I > realised that this patch > > http://www.kernel.org/git/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=92934bcbf96bc9dc931c40ca5f1a57685b7b813b > > makes a difference: current 2.6 works with the following code sequence > as expected (printk is executed), 2.4 fails. > > > #include <asm/bitops.h> > #include <linux/module.h> > > unsigned long a = 1; > > int module_init(void) > { > unsigned long b = 0; > int x; > > x = __test_and_set_bit(0, &b); > if (__test_and_set_bit(0, &a)) > printk("x = %d\n", x); > > return -1; > } > > > There will likely be a way to work around my issue. Nevertheless, I > wondered if that patch was already considered for 2.4 inclusion. Or is > there no risk that in-tree code is affected?
While I remember some discussion on the subject for 2.6, I don't recall anything similiar in 2.4. Wouldn't you happen to build with gcc-3.4 ? IIRC, the clobbering changed around this version. Could you confirm that the patch you pointed above fixes the problem for your case ?
Thanks in advance, Willy
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