Re: [Crash-utility] display function parameters for call stack

----- Original Message ----- > > Dave, > > > On Fri, Sep 21, 2012 at 9:44 PM, Dave Anderson < anderson(a)redhat.com > > wrote: > > > > > > ----- Original Message ----- > > > > Hi Dave, > > > > > > I notice there was some discussion around on enabling > > the display function parameters feature for crash tool. > > Like this one: > > http://www.redhat.com/archives/crash-utility/2009-May/msg00016.html > > Yes, it seems to come up every few years. People have tried, but it > has never come to fruition. > > > > > > Although the answer seems to be quite clear, it should be hard to > > support such feature. But does this feature cannot be done anyway? > > I think this feature would be great in assisting kernel debug. > > > > The main feature I require, first should be know each param's value in the call stack. > > Then it is better to know each call stack's param's name. > > > > Like for do_vfs_ioctl function, it is better to display as: > > do_vfs_ioctl(filp=xxx, fd=xxx, cmd=xxx, arg=xxx) > > > > Do you have any idea on how this could be implemented? > > No I don't. > > > > Sorry for asking the stupid question, but I notice that we could > get the structure member in crash by "struct" command: > > crash> struct stackframe > struct stackframe { > long unsigned int fp; > long unsigned int sp; > long unsigned int lr; > long unsigned int pc; > } > SIZE: 16 > > > I check the crash code, and find cmd_struct use gdb interface to > parse it out. > > > And the gdb itself seems already could parse out function argument[1], so could > we still use similar mechanism as the "struct" command to implement a "func" > command, which could shows the function declaration? You can either use the "whatis" command to get the function declaration: crash> help whatis NAME whatis - search symbol table for data or type information SYNOPSIS whatis [struct | union | typedef | symbol] DESCRIPTION This command displays the definition of structures, unions, typedefs or text/data symbols. ... crash> whatis do_vfs_ioctl int do_vfs_ioctl(struct file *, unsigned int, unsigned int, long unsigned int); crash> Or print it with "p", which gives you both the declaration and its virtual address: crash> p do_vfs_ioctl do_vfs_ioctl = $14 = {int (struct file *, unsigned int, unsigned int, long unsigned int)} 0xffffffff811247ec <do_vfs_ioctl> crash>

Dave