Re: [Crash-utility] Another parsing bug -- likely confusion caused by open parenthesis

----- Original Message ----- > crash> p/x *(*(struct trace_page*)0xFFFF8804125CBA60).page | sed > 's/^\$[0-9]* =/0xFFFF8804125CBA60 =/' >> trace-data.txt\n > gdb: gdb request failed: p/x *(*(struct > trace_page*)0xFFFF8804125CBA60).page | sed 's/^\$[0-9]* > =/0xFFFF8804125CBA60 =/' > crash> p/x *(*(struct trace_page*)0xFFFF8804125CBA60).page > $1467 = { > flags = 0x200000000000000, > _count = { > counter = 0x1 > }, > { > _mapcount = { > counter = 0xffffffff > }, > { > inuse = 0xffff, > objects = 0xffff > } > }, > { > { > private = 0x0, > mapping = 0x0 > }, > ptl = { > raw_lock = { > slock = 0x0 > } > }, > slab = 0x0, > first_page = 0x0 > }, > { > index = 0x0, > freelist = 0x0, > reserve = 0x0, > frag_count = { > counter = 0x0 > } > }, > lru = { > next = 0xdead000000100100, > prev = 0xdead000000200200 > } > } Bruce, I'm not sure what you mean about the "open parenthesis", but I think this simpler example shows the problem, which is related to using a native gdb command in conjunction with a pipe and a redirect. The "p" command is sort of a "convenience" crash command that pretty much exists to be able to quickly change the output radix before passing the request to the gdb module. Using just "p" alone defaults to the current output radix (decimal by default): crash> p jiffies jiffies = $12 = 4294754313 crash> The output radix can be changed by entering the "hex" alias, and then the same command above. Or alternatively, either "p -x" or the "px" alias can be used: crash> px jiffies jiffies = $13 = 0xfffcc009 crash> Piping the output works: crash> px jiffies | cat jiffies = $14 = 0xfffcc009 crash> Piping the output, and then redirecting it works: crash> px jiffies | cat > /tmp/junk crash> !cat /tmp/junk jiffies = $15 = 0xfffcc009 crash> But using the gdb "p/x" command directly (bypassing the crash "p" command), in conjunction with a pipe and a redirect, generates the failure. Just a pipe or a redirect alone works OK: crash> p/x jiffies | cat $16 = 0xfffcc009 crash> p/x jiffies > /tmp/junk crash> !cat /tmp/junk $17 = 0xfffcc009 crash> But using a pipe and a redirect strips the redirect, but leaves the "| cat" attached to the end of the command line sent to gdb: crash> p/x jiffies | cat > /tmp/junk gdb: gdb request failed: p/x jiffies | cat crash> Interesting that several pipes can be used, with the same bug showing up: crash> p/x jiffies | cat | cat > /tmp/junk gdb: gdb request failed: p/x jiffies | cat | cat crash> Not sure why just yet, other than there's a difference in the way native gdb commands and crash commands are processed. Let me dig into it...