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 - To unsubscribe from this list: send the line "unsubscribe dccp" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
