the disassembly of the sched_getcpu() code at runtime looks like: 0x2000000000203940 <+0>: [MMI] alloc r32=ar.pfs,9,1,0 0x2000000000203941 <+1>: adds r14=8,r13 0x2000000000203942 <+2>: mov r33=r12;; 0x2000000000203950 <+16>: [MMI] ld8 r14=[r14] 0x2000000000203951 <+17>: nop.m 0x0 0x2000000000203952 <+18>: mov r15=1304 0x2000000000203960 <+32>: [MII] mov r35=r0 <<<<<<<<<<<<<<<<<<< 0x2000000000203961 <+33>: mov r34=r0;;<<<<<<<<<<<<<<<<<<< 0x2000000000203962 <+34>: mov b7=r14;; 0x2000000000203970 <+48>: [MIB] nop.m 0x0 0x2000000000203971 <+49>: nop.i 0x0 0x2000000000203972 <+50>: br.call.sptk.many b6=b7;; When the "br.call" is executed, we flip to the new register frame and r34/r35 in the sched_getcpu() frame become r32/r33 in the new frame. So you get -EFAULT because the VDSO tries to dereference a NULL pointer for each of the *cpu and *node arguments. -Tony -- To unsubscribe from this list: send the line "unsubscribe linux-ia64" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
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