Willy Tarreau wrote: > 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 I used gcc 3.3.6-13 (Debian). > you confirm that the patch you pointed above fixes the problem for > your case ? Yes. I ported the x86 part back to 2.4.33 and my problem disappeared. Jan
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