Version:           0.8.80 (using 4.2.91 (KDE 4.2.91 (KDE 4.3 >= 20090609)), Gentoo)
Compiler:          i686-pc-linux-gnu-gcc
OS:                Linux (i686) release 2.6.29-gentoo-r3

Sometimes, when viewing a pdf file, Okular suddenly crashes. I had this issues with several PDF files, and it happens randomly, meaning that it works correctly for some time, then it crashes. If I restart Okular and open the same file, it works correctly again.

A fact I found strange is that the crash doesn't launch drkonqi, which is launched every time every other KDE application crashes. Here's the backtrace from gdb:

#0  0xb7f1c430 in __kernel_vsyscall ()
#1  0xb6947980 in raise (sig=6) at ../nptl/sysdeps/unix/sysv/linux/raise.c:64
#2  0xb69491c8 in abort () at abort.c:88
#3  0xb69897f3 in malloc_printerr (action=2, str=0xb6a44687 "free(): invalid pointer", ptr=0x8405848) at malloc.c:6201
#4  0xb698df2c in __libc_free (mem=0x6) at malloc.c:3677
#5  0xb32d7381 in gfree (p=0x0) at gmem.cc:290
#6  0xb324c9af in ~Dict (this=0x8413e48) at Dict.cc:66
#7  0xb329c328 in Object::free (this=0x845dac8) at Object.cc:138
#8  0xb32ab30d in ~BaseStream (this=0x845dac0) at Stream.cc:366
#9  0xb32ab359 in ~EmbedStream (this=0x845dac0) at Stream.cc:865
#10 0xb32638ab in Gfx::opBeginImage (this=0x84c7968, args=0xb31ba8b0, numArgs=0) at Gfx.cc:4125
#11 0xb3259d6c in Gfx::execOp (this=0x84c7968, cmd=0xb31baa50, args=0xb31ba8b0, numArgs=0) at Gfx.cc:772
#12 0xb325a2a7 in Gfx::go (this=0x84c7968, topLevel=0) at Gfx.cc:643
#13 0xb325cc97 in Gfx::display (this=0x84c7968, obj=0xb31bacc4, topLevel=0) at Gfx.cc:612
#14 0xb326177b in Gfx::doShowText (this=0x84c7968, s=0x84b7e88) at Gfx.cc:3412
#15 0xb32647f9 in Gfx::opShowSpaceText (this=0x84c7968, args=0xb31bae10, numArgs=1) at Gfx.cc:3327
#16 0xb3259d6c in Gfx::execOp (this=0x84c7968, cmd=0xb31bafb0, args=0xb31bae10, numArgs=1) at Gfx.cc:772
#17 0xb325a2a7 in Gfx::go (this=0x84c7968, topLevel=1) at Gfx.cc:643
#18 0xb325cc97 in Gfx::display (this=0x84c7968, obj=0xb31bb08c, topLevel=1) at Gfx.cc:612
#19 0xb329ff2c in Page::displaySlice (this=0x8421588, out=0x84d04b0, hDPI=149.73894462400631, vDPI=149.66325767024196, rotate=0, useMediaBox=0, crop=1, sliceX=-1, sliceY=-1, sliceW=-1, sliceH=-1,
    printing=0, catalog=0x845d3a8, abortCheckCbk=0, abortCheckCbkData=0x0, annotDisplayDecideCbk=0, annotDisplayDecideCbkData=0x0) at Page.cc:442
#20 0xb32a3425 in PDFDoc::displayPageSlice (this=0x83d01f8, out=0x84d04b0, page=8, hDPI=149.73894462400631, vDPI=149.66325767024196, rotate=0, useMediaBox=0, crop=1, printing=0, sliceX=-1, sliceY=-1,
    sliceW=-1, sliceH=-1, abortCheckCbk=0, abortCheckCbkData=0x0, annotDisplayDecideCbk=0, annotDisplayDecideCbkData=0x0) at PDFDoc.cc:423
#21 0xb33960cd in Poppler::Page::renderToImage (this=0x84d0270, xres=149.73894462400631, yres=149.66325767024196, x=-1, y=-1, w=-1, h=-1, rotate=Poppler::Page::Rotate0) at poppler-page.cc:205
#22 0xb3416c41 in PDFPixmapGeneratorThread::run (this=0x80c1860) at /var/tmp/paludis/kde-base-okular-scm/work/okular/okular/generators/poppler/generator_pdf.cpp:1708
#23 0xb73c80c0 in QThreadPrivate::start (arg=0x80c1860) at thread/qthread_unix.cpp:189
#24 0xb7346440 in start_thread () from /lib/libpthread.so.0
#25 0xb69eea2e in clone () at ../sysdeps/unix/sysv/linux/i386/clone.S:130

In the short description I suggested this can be more a poppler problem than an Okular problem because most of the backtrace seems to come from poppler itself. My poppler version is 10.7