Messages in this thread | | | From | Keith Owens <> | Subject | Re: Functions with Large Stack Usage | Date | Wed, 28 Aug 2002 13:56:17 +1000 |
| |
On 27 Aug 2002 14:08:24 -0400, Danny Cox <danscox@mindspring.com> wrote: > After having read of the stack overflow "issues" awhile back, a couple >of ideas gelled, with this script as a result. The script finds >functions that use a large (changeable) amount of stack space. Note: >it's heuristic, it's static, it only looks at compiled-in functions, and >says nothing about the dynamic system. It DOES point out functions that >may (MAY) need to be examined closer. >... > How it works: With Keith Owens' KDB patch, one may compile the kernel >with frame pointers. With the Disassemble::X86 Perl module from CPAN >(http://search.cpan.org/author/BOBMATH/Disassemble-X86-0.12/X86.pm), >it's easy. It requires the vmlinux and System.map files, and for each >function looks at the first 10 instructions for the 'sub esp,N'. The N >is the number of bytes of stack used.
No need for frame pointers, or Perl. Run as
kernel.stack vmlinux $(/sbin/modprobe -l)
#!/bin/bash # # Run a compiled ix86 kernel and print large local stack usage. # # />:/{s/[<>:]*//g; h; } On lines that contain '>:' (headings like # c0100000 <_stext>:), remove <, > and : and hold the line. Identifies # the procedure and its start address. # # /subl\?.*\$0x[^,][^,][^,].*,%esp/{ Select lines containing # subl\?...0x...,%esp but only if there are at least 3 digits between 0x and # ,%esp. These are local stacks of at least 0x100 bytes. # # s/.*$0x\([^,]*\).*/\1/; Extract just the stack adjustment # /^[89a-f].......$/d; Ignore line with 8 digit offsets that are # negative. Some compilers adjust the stack on exit, seems to be related # to goto statements # G; Append the held line (procedure and start address). # s/\(.*\)\n.* \(.*\)/\1 \2/; Remove the newline and procedure start # address. Leaves just stack size and procedure name. # p; }; Print stack size and procedure name. # # /subl\?.*%.*,%esp/{ Selects adjustment of %esp by register, dynamic # arrays on stack. # G; Append the held line (procedure and start address). # s/\(.*\)\n\(.*\)/Dynamic \2 \1/; Reformat to "Dynamic", procedure # start address, procedure name and the instruction that adjusts the # stack, including its offset within the proc. # p; }; Print the dynamic line. # # # Leading spaces in the sed string are required. # objdump --disassemble "$@" | \ sed -ne '/>:/{s/[<>:]*//g; h; } /subl\?.*\$0x[^,][^,][^,].*,%esp/{ s/.*\$0x\([^,]*\).*/\1/; /^[89a-f].......$/d; G; s/\(.*\)\n.* \(.*\)/\1 \2/; p; }; /subl\?.*%.*,%esp/{ G; s/\(.*\)\n\(.*\)/Dynamic \2 \1/; p; }; ' | \ sort
- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
| |