On Wed, May 7, 2008 at 3:07 PM, Avi Nehori <[EMAIL PROTECTED]> wrote: > I'm using 2.4.21 kernel (and also tried 2.6.18 with the same behavior). > the memory address is being written through a kernel module . > please see below : > > [0]kdb> md 0xa0f7bc94 > 0xa0f7bc94 00000000 00000001 00000003 00000000 ................ > [0]kdb> bpha 0xa0f7bc94 dataw 4 Okay, please can you run "rd d" at this moment to display the debug registers(and paste out the result of course), I somewhat feel DR0-DR3 were not changed but actually they are supposed to represent the breakpoint location virtual address.
Regards Jason > [0]kdb> go > > > the breakpoint is not called even though the memory address being changed: > [0]kdb> md 0xa0f7bc94 > 0xa0f7bc94 00000064 00000001 00000003 00000000 d............... > > > > > jidong xiao wrote: > > On Wed, May 7, 2008 at 2:41 PM, Avi Nehori <[EMAIL PROTECTED]> wrote: > > > > > > > Thanks for your reply Jay, > > > I'm running i386 and the thing is that when i set the breakpoint on a > > > memory address(trying to catch a memory > > > corruption bug) the watch point is not getting hit when the memory is > > > written. > > > I'm following the kdb documentation which says : > > > > > > "The |bph| and |bpha| commands can be used (provided the architecture > > > supports use of hardware registers) to apply read and write breakpoints. > > > This means we can get control whenever data is read from or written into > > > a particular address. This can be extremely handy when debugging > > > data/memory corruption problems, where you can use it to identify the > > > corrupting code/process." > > > > > > *Examples* > > > > > > *To enter the kernel debugger whenever four bytes are written into > > > address 0xc0204060:* > > > | [0]kdb> bph 0xc0204060 dataw 4 > > > > > > > > > so i followed the documentation and set a breakpoint using bph (and > > > also bpha) on a memory address > > > exactly as the above example ,but when i modify the memory address > > > ,the breakpoint does not hit.... > > > any idea what is wrong here ? > > > any help will be very appreciated . > > > Thanks! > > > > > > > > > > > > > What the kernel version are you using? and how do you modify the memory > address? > > > > Regards > > Jason Xiao > > > > > > > > > || > > > > > > > > > || > > > | > > > > > > > > > > > > > > > Jay Lan wrote: > > > > > > > > > > Avi Nehori wrote: > > > > > > > > > > > > > > > > > Hi, > > > > > I'm trying to set a watch point with bpha as follows : > > > > > bpha address dataw 4 > > > > > but the watchpoint is never called when the memory address is > changed. > > > > > is it a know bug ? > > > > > is there a patch ? > > > > > > > > > > > > > > > > > > > I heard bph/bpha worked on x86_64. However, hardware breakpoint > > > > was not implemented on IA64. Were you on IA64? > > > > > > > > Greg Banks of SGI ([EMAIL PROTECTED]) provided patches for IA64. Many > > > > thanks to Greg! > > > > 1) gnb-kdb-implement-bpha-v3 > > > > This patch implemented bph/bpha on IA64. > > > > 2) gnb-test-kdb-bph > > > > This patch provided a test infrastructure to test all the ia64 > > > > data* breakpoint features. > > > > > > > > I have uploaded the patches to the download area. > > > > ftp://oss.sgi.com/projects/kdb/download/v4.4 > > > > > > > > > > > > Cheers, > > > > - jay > > > > > > > > > > > > > > > > > > > > > Thanks. > > > > > --------------------------- > > > > > Use http://oss.sgi.com/ecartis to modify your settings or to > unsubscribe. > > > > > > > > > > > > > > > > > > > > > > > Scanned by Check Point Total Security Gateway. > > > > > > > > > > > --------------------------- > > > Use http://oss.sgi.com/ecartis to modify your settings or to > unsubscribe. > > > > > > > > > > > > > Scanned by Check Point Total Security Gateway. > > > > > > > --------------------------- Use http://oss.sgi.com/ecartis to modify your settings or to unsubscribe.
