From 48442540e4c481474c4493192cbd9cb58c5016ad Mon Sep 17 00:00:00 2001 From: Vineet Gupta Date: Fri, 7 Oct 2016 14:11:17 -0700 Subject: ARC: nptl: cancellable wrappers were broken #2 Despite the prev fix, tst-mqueue3 was still segfaulting. The issue was BLINK register not restored properly for return 00002690 : 2690: sub r9,r25,0x448 2698: ld r10,[r9] 269c: cmp r10,0 26a0: beq -36 26a4: st.aw blink,[sp,-4] 26a8: st.aw r0,[sp,-4] 26ac: st.aw r1,[sp,-4] 26b0: st.aw r2,[sp,-4] 26b4: st.aw r3,[sp,-4] 26b8: st.aw r4,[sp,-4] 26bc: bl 1e28 <__librt_enable_asynccancel> 26c0: mov r9,r0 26c4: ld.ab r4,[sp,4] 26c8: ld.ab r3,[sp,4] 26cc: ld.ab r2,[sp,4] 26d0: ld.ab r1,[sp,4] 26d4: ld.ab r0,[sp,4] 26d8: ld.ab blink,[sp, 4] <---- function return BLINK 26dc: mov r8,182 26e0: trap_s 0 26e2: cmp r0,-1024 26e6: st.aw r0,[sp,-4] 26ea: mov r0,r9 26ee: bl 1e90 <__librt_disable_asynccancel> <-- BLINK clobbered to next PC 26f2: ld.ab r0,[sp,4] <----| loops here until sp is out of bound 26fa: cmp r0,-1024 | 26fe: jls [blink] -----| 2702: b 15d8 2706: nop_s So the fix was to retain BLINK on stack before function call, and pop it later - 26d8: ld.ab blink,[sp, 4] + 26d8: ld blink,[sp] <--- restore BLINK, but retain on stack 26dc: mov r8,182 26e0: trap_s 0 26e2: cmp r0,-1024 26e6: st.aw r0,[sp,-4] 26ea: mov r0,r9 26ee: bl 1e90 <__librt_disable_asynccancel> 26f2: ld.ab r0,[sp,4] + 26f6: ld.ab blink,[sp,4] <--- finally pop BLINK 26fa: cmp r0,-1024 26fe: jls [blink] Reported-by: Eugeniy Paltsev Cc: Alexey Brodkin Signed-off-by: Vineet Gupta --- libpthread/nptl/sysdeps/unix/sysv/linux/arc/sysdep-cancel.h | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/libpthread/nptl/sysdeps/unix/sysv/linux/arc/sysdep-cancel.h b/libpthread/nptl/sysdeps/unix/sysv/linux/arc/sysdep-cancel.h index 918f61d67..01fd844d1 100644 --- a/libpthread/nptl/sysdeps/unix/sysv/linux/arc/sysdep-cancel.h +++ b/libpthread/nptl/sysdeps/unix/sysv/linux/arc/sysdep-cancel.h @@ -38,6 +38,7 @@ mov r0, r9 /* prep mask for disable_asynccancel */ ` \ CDISABLE ` \ pop r0 /* get syscall ret value back */ ` \ + pop blink /* UNDOCARGS above left blink on stack */ ` \ cmp r0, -1024 ` \ jls [blink] ` \ b __syscall_error@plt ` \ @@ -75,7 +76,9 @@ .endm #define DOCARGS_0 push blink -#define UNDOCARGS_0 pop blink + +/* don't pop blink at this point */ +#define UNDOCARGS_0 ld blink, [sp] #define DOCARGS_1 DOCARGS_0` push r0 #define UNDOCARGS_1 pop r0` UNDOCARGS_0 -- cgit v1.2.3