Messages in this thread Patch in this message | ![/](/images/icornerl.gif) | | From | Jiri Slaby <> | Subject | [PATCH 1/1] x86/vdso: fix a reference to a non-existing instruction | Date | Thu, 5 Mar 2015 09:13:31 +0100 |
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.LSTARTFDEDLSI1 says: /* HACK: The dwarf2 unwind routines will subtract 1 from the return address to get an address in the middle of the presumed call instruction. Since we didn't get here via a call, we need to include the nop before the real start to make up for it. */ .long .LSTART_sigreturn-1-. /* PC-relative start address */
But commit 69d0627a7f6e891189124d784d2fa90cae7c449a (x86 vDSO: reorder vdso32 code) from 2.6.25 replaced .org __kernel_vsyscall+32,0x90 by ALIGN right before __kernel_sigreturn. Of course, ALIGN need not generate any nop in there. Esp. gcc5 collapses vclock_gettime.o and int80.o together with no generated nops as "ALIGN". In that case kernel does not even link: ld: .eh_frame_hdr table[4] FDE at 0000000000000648 overlaps table[5] FDE at 0000000000000670.
So fix this by adding there at least a single nop and make the function ALIGN possibly with more nops then.
Kudos for reporting and diagnosing should go to Richard.
Signed-off-by: Jiri Slaby <jslaby@suse.cz> Reported-by: Richard Biener <rguenther@suse.de> Cc: stable@vger.kernel.org Cc: Andy Lutomirski <luto@amacapital.net> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@redhat.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: x86@kernel.org --- arch/x86/vdso/vdso32/sigreturn.S | 1 + 1 file changed, 1 insertion(+)
diff --git a/arch/x86/vdso/vdso32/sigreturn.S b/arch/x86/vdso/vdso32/sigreturn.S index 31776d0efc8c..d7ec4e251c0a 100644 --- a/arch/x86/vdso/vdso32/sigreturn.S +++ b/arch/x86/vdso/vdso32/sigreturn.S @@ -17,6 +17,7 @@ .text .globl __kernel_sigreturn .type __kernel_sigreturn,@function + nop /* this guy is needed for .LSTARTFDEDLSI1 below (watch for HACK) */ ALIGN __kernel_sigreturn: .LSTART_sigreturn: -- 2.3.0
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