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Rockbox mail archiveSubject: Re: Segfault with Faster MDCT patch and -fPICRe: Segfault with Faster MDCT patch and -fPIC
From: Slawomir Testowy <slawomir.testowy_at_gmail.com>
Date: Mon, 20 Sep 2010 11:00:01 +0200 2010/9/17 Rafaël Carré <rafael.carre_at_gmail.com>: > On Fri, 17 Sep 2010 16:26:31 +0200 > Slawomir Testowy <slawomir.testowy_at_gmail.com> wrote: > >> 2010/9/17 Rafaël Carré <rafael.carre_at_gmail.com>: >> > On Fri, 17 Sep 2010 14:01:48 +0200 >> > Slawomir Testowy <slawomir.testowy_at_gmail.com> wrote: >> > >> >> Hi, >> >> >> >> thanks for quick response. >> >> >> >> 2010/9/17 Rafaël Carré <rafael.carre_at_gmail.com>: >> >> > I think the OP should post .S output of gcc and also give >> >> > us compiler version and options being used >> >> > >> >> > -- >> >> > Rafaël Carré >> >> > >> >> >> >> Here it is: >> >> >> >> /opt/freescale/usr/local/gcc-4.1.2-glibc-2.5-nptl-3/arm-none-linux-gnue >> >> abi/bin/arm-none-linux-gnueabi-gcc --version >> >> arm-none-linux-gnueabi-gcc (GCC) 4.1.2 >> >> Copyright (C) 2006 Free Software Foundation, Inc. >> >> This is free software; see the source for copying conditions. >> >> There is NO warranty; not even for MERCHANTABILITY or FITNESS FOR >> >> A PARTICULAR PURPOSE. >> >> >> >> Exact command line: >> >> >> >> /opt/freescale/usr/local/gcc-4.1.2-glibc-2.5-nptl-3/arm-none-linux-gnue >> >> abi/bin/arm-none-linux-gnueabi-gcc -std=gnu89 -fPIC -DHAVE_CONFIG_H >> >> -I. -I./ -O2 -D_ARM_ASSEM_ -fsigned-char -ffast-math >> >> -fsingle-precision-constant -D_REENTRANT -DUSE_MEMORY_H -MT >> >> fft-ffmpeg.lo -MD -MP -MF .deps/fft-ffmpeg.Tpo -c fft-ffmpeg.c -o >> >> fft-ffmpeg.o >> >> >> >> Outputs of gcc -S and gcc -E are included in attachments. >> >> >> >> I'm afraid I won't be able to test proposed patch today. I'll try >> >> on Monday. >> > >> > I think the patch wouldn't compile on ARM because I missed the ldmia >> > ordering constraints like Dave mentioned >> > >> > otherwise I see that fft8_dispatch only differs on 1 register (-fPIC >> > use r9 and without it uses r10==sl) but I don't see r10/sl being >> > used as a pointer.. perhaps it's only done at linking phase? >> > >> > BTW building gdb should be as simple as: >> > ./configure --target=arm-none-linux-gnueabi ; make >> > >> > -- >> > Rafaël Carré >> > >> >> I managed to build gdbserver + gdb. Here is the stacktrace: >> >> Program received signal SIGSEGV, Segmentation fault. >> 0x0003b3a0 in pass (z_arg=<value optimized out>, >> STEP_arg=<value optimized out>, n_arg=<value optimized out>) >> at fft-ffmpeg.c:243 >> 243 w += STEP; >> (gdb) bt >> #0 0x0003b3a0 in pass (z_arg=<value optimized out>, >> STEP_arg=<value optimized out>, n_arg=<value optimized out>) >> at fft-ffmpeg.c:243 >> #1 0x0003c080 in fft64 (z=0x1b10190) at fft-ffmpeg.c:355 >> #2 0x0003c0b0 in fft128 (z=0x1b10190) at fft-ffmpeg.c:356 >> #3 0x0003c0e0 in fft256 (z=0x1b10190) at fft-ffmpeg.c:357 >> #4 0x0003b924 in ff_fft_calc_c (nbits=<value optimized out>, >> z=0x1ae2dc0) at fft-ffmpeg.c:370 >> #5 0x0003ad78 in ff_imdct_half (nbits=28199880, output=0x1b100c8, >> input=<value optimized out>) at mdct-ffmpeg.c:112 >> #6 0x0003b178 in ff_imdct_calc (nbits=28377488, output=0x1afa5c8, >> input=0x0) at mdct-ffmpeg.c:348 >> #7 0x0003a5ac in mapping0_inverse (vb=0xbef3c670, l=0x1b0b538) >> at mapping0.c:290 >> #8 0x00033270 in vorbis_synthesis (vb=0xbef3c670, op=<value >> optimized out>, decodep=1) at synthesis.c:75 >> >> Unfortunately, most values are optimized out. On Monday, I will >> rebuild tremor with -O0 and try again. > > 'info all-registers' + 'disass $pc-32 $pc+32' can give a hint also > (from http://ffmpeg.org/bugreports.html) Here it is: (gdb) info all-registers r0 0x1b10190 28377488 r1 0x1ae2dc0 28192192 r2 0x0 0 r3 0x100 256 r4 0x0 0 r5 0x0 0 r6 0x0 0 r7 0x0 0 r8 0x0 0 r9 0x0 0 r10 0x0 0 r11 0x40 64 r12 0x400 1024 sp 0xbeeb7450 0xbeeb7450 lr 0x0 0 pc 0x3b3a0 0x3b3a0 <pass+360> f0 0 (raw 0x0003f8cc0000000000000000) f1 0 (raw 0x0003f8cc0000000000000000) f2 0 (raw 0x0003f8cc0000000000000000) f3 0 (raw 0x0003f8cc0000000000000000) f4 0 (raw 0x0003f8cc0000000000000000) f5 0 (raw 0x0003f8cc0000000000000000) f6 0 (raw 0x0003f8cc0000000000000000) f7 0 (raw 0x0003f8cc0000000000000000) fps 0x0 0 cpsr 0x60000010 1610612752 (gdb) disass $pc-32 $pc+32 A syntax error in expression, near `$pc+32'. (gdb) disass $pc-32 Dump of assembler code for function pass: 0x0003b238 <+0>: push {r4, r5, r6, r7, r8, r9, r10, r11, lr} 0x0003b23c <+4>: lsl r1, r1, #2 0x0003b240 <+8>: sub sp, sp, #44 ; 0x2c 0x0003b244 <+12>: ldr r10, [pc, #1252] ; 0x3b730 <pass+1272> 0x0003b248 <+16>: str r1, [sp, #16] 0x0003b24c <+20>: ldr r3, [pc, #1248] ; 0x3b734 <pass+1276> 0x0003b250 <+24>: lsl r1, r2, #4 0x0003b254 <+28>: add r10, pc, r10 0x0003b258 <+32>: str r1, [sp, #20] 0x0003b25c <+36>: ldr r12, [sp, #20] 0x0003b260 <+40>: ldr r1, [r10, r3] 0x0003b264 <+44>: ldr r3, [sp, #16] 0x0003b268 <+48>: add r0, r0, r12 0x0003b26c <+52>: add r1, r3, r1 0x0003b270 <+56>: ldm r0, {r5, r6} 0x0003b274 <+60>: lsl r11, r2, #3 0x0003b278 <+64>: add r0, r0, r11 0x0003b27c <+68>: ldm r0, {r7, r8} 0x0003b280 <+72>: lsl r2, r2, #5 0x0003b284 <+76>: rsb r2, r11, r2 0x0003b288 <+80>: str r2, [sp, #24] 0x0003b28c <+84>: ldr r12, [sp, #24] 0x0003b290 <+88>: rsb r3, r8, r6 0x0003b294 <+92>: rsb r2, r5, r7 0x0003b298 <+96>: rsb r0, r12, r0 0x0003b29c <+100>: add r4, r7, r5 0x0003b2a0 <+104>: add r6, r6, r8 0x0003b2a4 <+108>: ldm r0, {r9, r10} 0x0003b2a8 <+112>: add r9, r4, r9 0x0003b2ac <+116>: add r10, r6, r10 0x0003b2b0 <+120>: sub r4, r9, r4, lsl #1 0x0003b2b4 <+124>: sub r6, r10, r6, lsl #1 0x0003b2b8 <+128>: stm r0, {r9, r10} 0x0003b2bc <+132>: add r0, r11, r0 0x0003b2c0 <+136>: ldm r0, {r9, r10} 0x0003b2c4 <+140>: add r9, r3, r9 0x0003b2c8 <+144>: add r10, r2, r10 0x0003b2cc <+148>: sub r7, r9, r3, lsl #1 0x0003b2d0 <+152>: sub r8, r10, r2, lsl #1 0x0003b2d4 <+156>: stm r0, {r9, r10} 0x0003b2d8 <+160>: add r0, r11, r0 0x0003b2dc <+164>: stm r0, {r4, r6} 0x0003b2e0 <+168>: add r0, r11, r0 0x0003b2e4 <+172>: stm r0, {r7, r8} 0x0003b2e8 <+176>: rsb r0, r12, r0 0x0003b2ec <+180>: add r0, r0, #8 0x0003b2f0 <+184>: ldm r1, {r4, r12} 0x0003b2f4 <+188>: ldr r2, [sp, #20] 0x0003b2f8 <+192>: add r0, r2, r0 0x0003b2fc <+196>: ldm r0, {r9, r10} 0x0003b300 <+200>: smull r3, r8, r12, r9 0x0003b304 <+204>: rsb r6, r9, #0 0x0003b308 <+208>: smlal r3, r8, r4, r10 0x0003b30c <+212>: smull r3, r6, r4, r6 0x0003b310 <+216>: smlal r3, r6, r12, r10 0x0003b314 <+220>: add r0, r11, r0 > > btw you mentioned TRANSFORM_EQUAL (only used in fft8) in your first mail > but this time it's in a different function, a different crash? > > -- > Rafaël Carré > Yeah, just like I stated before I was putting printf's in all functions to find out the cause of segfault. These calls could change something. -- regards, Slawomir TestowyReceived on 2010-09-20 Page template was last modified "Tue Sep 7 00:00:02 2021" The Rockbox Crew -- Privacy Policy |