Attachment 16350 Details for Bug 15807 – gdb steps through a memory write which he can't read

gdb steps through a memory write which he can't read

xf86-video-intel-with-mprotect-enabled-invalid-access.log (text/x-log), 8.32 KB, created by Hugo Mildenberger on 2008-05-04 14:01:53 UTC

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Creator: Hugo Mildenberger

Created: 2008-05-04 14:01:53 UTC

Size: 8.32 KB

patch

obsolete

>g90-03-06 ~ # pgrep X
>2733 <- this is the one and only session I currently use for writing the bug comment
>g90-03-06 ~ # gdb
>GNU gdb 6.8
>Copyright (C) 2008 Free Software Foundation, Inc.
>License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>
>This is free software: you are free to change and redistribute it.
>There is NO WARRANTY, to the extent permitted by law.  Type "show copying"
>and "show warranty" for details.
>This GDB was configured as "i686-pc-linux-gnu".
>(gdb) attach 2733
>Attaching to process 2733
>Reading symbols from /usr/bin/Xorg...done.
>Reading symbols from /usr/lib/libpciaccess.so.0...done.
>Loaded symbols for /usr/lib/libpciaccess.so.0
>Reading symbols from /lib/libdl.so.2...done.
>Loaded symbols for /lib/libdl.so.2
>Reading symbols from /usr/lib/libXfont.so.1...done.
>Loaded symbols for /usr/lib/libXfont.so.1
>Reading symbols from /usr/lib/libfreetype.so.6...done.
>Loaded symbols for /usr/lib/libfreetype.so.6
>Reading symbols from /usr/lib/libXau.so.6...done.
>Loaded symbols for /usr/lib/libXau.so.6
>Reading symbols from /usr/lib/libfontenc.so.1...done.
>Loaded symbols for /usr/lib/libfontenc.so.1
>Reading symbols from /lib/libz.so.1...done.
>Loaded symbols for /lib/libz.so.1
>Reading symbols from /usr/lib/libpixman-1.so.0...done.
>Loaded symbols for /usr/lib/libpixman-1.so.0
>Reading symbols from /usr/lib/libhal.so.1...done.
>Loaded symbols for /usr/lib/libhal.so.1
>Reading symbols from /lib/libusb-0.1.so.4...done.
>Loaded symbols for /lib/libusb-0.1.so.4
>Reading symbols from /usr/lib/libdbus-1.so.3...done.
>Loaded symbols for /usr/lib/libdbus-1.so.3
>Reading symbols from /usr/lib/libXdmcp.so.6...done.
>Loaded symbols for /usr/lib/libXdmcp.so.6
>Reading symbols from /usr/lib/libcrypto.so.0.9.8...done.
>Loaded symbols for /usr/lib/libcrypto.so.0.9.8
>Reading symbols from /lib/libm.so.6...done.
>Loaded symbols for /lib/libm.so.6
>Reading symbols from /lib/librt.so.1...done.
>Loaded symbols for /lib/librt.so.1
>Reading symbols from /usr/lib/gcc/i686-pc-linux-gnu/4.2.3/libgcc_s.so.1...done.
>Loaded symbols for /usr/lib/gcc/i686-pc-linux-gnu/4.2.3/libgcc_s.so.1
>Reading symbols from /lib/libc.so.6...done.
>Loaded symbols for /lib/libc.so.6
>Reading symbols from /lib/ld-linux.so.2...done.
>Loaded symbols for /lib/ld-linux.so.2
>Reading symbols from /lib/libpthread.so.0...done.
>[Thread debugging using libthread_db enabled]
>[New Thread 0xb7bac8d0 (LWP 2733)]
>Loaded symbols for /lib/libpthread.so.0
>Reading symbols from /usr/lib/xorg/modules/fonts/libfreetype.so...done.
>Loaded symbols for /usr/lib/xorg/modules/fonts//libfreetype.so
>Reading symbols from /usr/lib/xorg/modules/extensions/libextmod.so...done.
>Loaded symbols for /usr/lib/xorg/modules/extensions//libextmod.so
>Reading symbols from /usr/lib/xorg/modules/extensions/libglx.so...done.
>Loaded symbols for /usr/lib/xorg/modules/extensions//libglx.so
>Reading symbols from /usr/lib/xorg/modules/extensions/libdri.so...done.
>Loaded symbols for /usr/lib/xorg/modules/extensions//libdri.so
>Reading symbols from /usr/lib/libdrm.so.2...done.
>Loaded symbols for /usr/lib/libdrm.so.2
>Reading symbols from /usr/lib/xorg/modules/extensions/libdbe.so...done.
>Loaded symbols for /usr/lib/xorg/modules/extensions//libdbe.so
>Reading symbols from /usr/lib/xorg/modules/extensions/libxtrap.so...done.
>Loaded symbols for /usr/lib/xorg/modules/extensions//libxtrap.so
>Reading symbols from /usr/lib/xorg/modules/fonts/libtype1.so...done.
>Loaded symbols for /usr/lib/xorg/modules/fonts//libtype1.so
>Reading symbols from /usr/lib/xorg/modules/extensions/libdri2.so...done.
>Loaded symbols for /usr/lib/xorg/modules/extensions//libdri2.so
>Reading symbols from /usr/lib/xorg/modules/drivers/intel_drv.so...done.
>Loaded symbols for /usr/lib/xorg/modules/drivers//intel_drv.so
>Reading symbols from /usr/lib/xorg/modules/input/kbd_drv.so...done.
>Loaded symbols for /usr/lib/xorg/modules/input//kbd_drv.so
>Reading symbols from /usr/lib/xorg/modules/input/mouse_drv.so...done.
>Loaded symbols for /usr/lib/xorg/modules/input//mouse_drv.so
>Reading symbols from /usr/lib/xorg/modules/libint10.so...done.
>Loaded symbols for /usr/lib/xorg/modules//libint10.so
>Reading symbols from /usr/lib/xorg/modules/libvbe.so...done.
>Loaded symbols for /usr/lib/xorg/modules//libvbe.so
>Reading symbols from /usr/lib/xorg/modules/libvgahw.so...done.
>Loaded symbols for /usr/lib/xorg/modules//libvgahw.so
>Reading symbols from /usr/lib/xorg/modules/drivers/sil164.so...done.
>Loaded symbols for /usr/lib/xorg/modules/drivers//sil164.so
>Reading symbols from /usr/lib/xorg/modules/libfb.so...done.
>Loaded symbols for /usr/lib/xorg/modules//libfb.so
>Reading symbols from /usr/lib/xorg/modules/libexa.so...done.
>Loaded symbols for /usr/lib/xorg/modules//libexa.so
>Reading symbols from /usr/lib/dri/i915_dri.so...done.
>Loaded symbols for /usr/lib/dri/i915_dri.so
>Reading symbols from /usr/lib/libexpat.so.1...done.
>Loaded symbols for /usr/lib/libexpat.so.1
>0xb8026424 in __kernel_vsyscall ()
>(gdb) br I830EmitFlush
>Breakpoint 1 at 0xb7a98cae: file i830_accel.c, line 29165.
>(gdb) cont
>Continuing.
>[Switching to Thread 0xb7bac8d0 (LWP 2733)]
>
>Breakpoint 1, I830EmitFlush (pScrn=0x820c608) at i830_accel.c:29165
>29165     I830Ptr pI830 = ((I830Ptr) ((pScrn)->driverPrivate));
>(gdb) next
>29166     int flags = (1 << 4) | (1 << 0);
>(gdb)
>29168     if (((pI830->PciInfo)->device_id == 0x29A2
>(gdb)
>29180           if (pI830->ring_emitting != 0)
>(gdb)
>29204           pI830->ring_emitting = (2) * 4;
>(gdb)
>29207           if (pI830->LpRing->space < pI830->ring_emitting)
>(gdb)
>29209           pI830->ring_next = pI830->LpRing->tail;
>(gdb)
>29212           pI830->ring_used = 0;
>(gdb)
>29235           *(volatile uint32_t *) (pI830->LpRing->virtual_start +
>(gdb)
>29237           pI830->ring_used += 4;
>(gdb) print pI830->LpRing
>$1 = (I830RingBuffer *) 0x8239b98
>(gdb) print *pI830->LpRing
>$2 = {tail_mask = 131071, mem = 0x82394a8, virtual_start = 0xaf935000 <Address 0xaf935000 out of bounds>, head = 80256,
>  tail = 80256, space = 131064}
>(gdb) list -4
>29223                 pI830->ring_next += 4;
>29224                 pI830->ring_next &= pI830->LpRing->tail_mask;
>29225               }
>29226             while (0);
>29227         }
>29228       while (0);
>29229       do
>29230         {
>29231           if (0 & 0x8)
>29232             ErrorF ("OUT_RING 0x%08x: 0x%08x, (mask %x)\n", pI830->ring_next,
>(gdb) list
>29233                     (unsigned int) ((0x04 << 23) | flags),
>29234                     pI830->LpRing->tail_mask);
>29235           *(volatile uint32_t *) (pI830->LpRing->virtual_start +
>29236                                   pI830->ring_next) = (0x04 << 23) | flags;
>29237           pI830->ring_used += 4;
>29238           pI830->ring_next += 4;
>29239           pI830->ring_next &= pI830->LpRing->tail_mask;
>29240         }
>29241       while (0);
>29242       do
>(gdb) print *(pI830->LpRing+pI830->ring_next)
>$3 = {tail_mask = 1868849453, mem = 0x682d6562, virtual_start = 0x65766c65 <Address 0x65766c65 out of bounds>,
>  head = 1633905012, tail = 1684368685, space = 762148201}
>(gdb) print *(pI830->LpRing)
>$4 = {tail_mask = 131071, mem = 0x82394a8, virtual_start = 0xaf935000 <Address 0xaf935000 out of bounds>, head = 80256,
>  tail = 80256, space = 131064}
>(gdb) print *(pI830->LpRing+pI830->ring_next)
>$5 = {tail_mask = 1868849453, mem = 0x682d6562, virtual_start = 0x65766c65 <Address 0x65766c65 out of bounds>,
>  head = 1633905012, tail = 1684368685, space = 762148201}
>(gdb) print *(pI830->LpRing->virtual_start+pI830->ring_next)
>Cannot access memory at address 0xaf948980
>(gdb) bt
>#0  I830EmitFlush (pScrn=0x820c608) at i830_accel.c:29237
>#1  0xb7ae86c1 in I830DRISwapContext (pScreen=0x8238418, syncType=2, oldContextType=1, oldContext=0x8239a70,
>    newContextType=1, newContext=0x8239a60) at i830_dri.c:1067
>#2  0xb801d7db in DRIDoWakeupHandler (screenNum=0, wakeupData=0x0, result=4294967295, pReadmask=0x81f3360) at dri.c:1639
>#3  0xb801d928 in DRIWakeupHandler (wakeupData=0x0, result=-1, pReadmask=0x81f3360) at dri.c:1608
>#4  0x0808e6c9 in WakeupHandler (result=-1, pReadmask=0x81f3360) at dixutils.c:418
>#5  0x0812b396 in WaitForSomething (pClientsReady=0x85831e8) at WaitFor.c:239
>#6  0x0808a9bd in Dispatch () at dispatch.c:372
>#7  0x080716ea in main (argc=8, argv=0xbfd40b34, envp=0xaf935000) at main.c:433
>(gdb) print *(uint32_t*)(pI830->LpRing->virtual_start+pI830->ring_next)
>Cannot access memory at address 0xaf948980
>(gdb) print *(volatile uint32_t*)(pI830->LpRing->virtual_start+pI830->ring_next)
>Cannot access memory at address 0xaf948980
>(gdb)

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Attachments on bug 15807: 16311 | 16312 | 16313 | 16314 | 16315 | 16346 | 16348 | 16350

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