Hi Ian, Not sure it's still useful after patch provide by Prasanna... But I tried to turn off CONFIG_DEBUG_RODATA and both `tcp_probe' and `dccp_probe' can be load properly. I also ran iperf test (for dccp) and it works. Patrick. On 07/06/07, Ian McDonald <ian.mcdonald@xxxxxxxxxxx> wrote:
On 6/7/07, Chuck Ebbert <cebbert@xxxxxxxxxx> wrote: > On 06/06/2007 04:47 PM, Ian McDonald wrote: > > Hi there, > > > > We've seen a report of a problem with dccp_probe as shown below. The > > user has also verified that it occurs in tcp_probe as well. This is on > > Dave Miller's tree but that currently tracks Linus' tree quite > > closely. I do note that it is around 2.6.22-rc2 timeframe so there is > > a possibility fixes may have gone in since. > > > > It faulted when it tried to write the breakpoint instruction into the > running kernel's executable code. Apparently the kernel code is now marked > read-only? > > Yes it would appear to be the case as user has CONFIG_DEBUG_RODATA set. Patrick - can you turn this off and retest? It's under Kernel Hacking, Write protect kernel read only data structures. The list of commits that I see around this are at: http://git.kernel.org/?p=linux%2Fkernel%2Fgit%2Ftorvalds%2Flinux-2.6.git&a=search&h=HEAD&st=commit&s=DEBUG_RODATA I suspect it's probably one of the latter ones giving the timing. I guess there are a couple of solutions here - either make kprobes conflict with CONFIG_DEBUG_RODATA so you can do one or the other, or look into more detail what access kprobes need. Ian -- Web: http://wand.net.nz/~iam4/ Blog: http://iansblog.jandi.co.nz WAND Network Research Group
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