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Diffstat (limited to 'Documentation/admin-guide/README.rst')
| -rw-r--r-- | Documentation/admin-guide/README.rst | 91 |
1 files changed, 7 insertions, 84 deletions
diff --git a/Documentation/admin-guide/README.rst b/Documentation/admin-guide/README.rst index 9eb6b9042f75..9a969c0157f1 100644 --- a/Documentation/admin-guide/README.rst +++ b/Documentation/admin-guide/README.rst @@ -262,8 +262,6 @@ Compiling the kernel - Make sure you have at least gcc 5.1 available. For more information, refer to :ref:`Documentation/process/changes.rst <changes>`. - Please note that you can still run a.out user programs with this kernel. - - Do a ``make`` to create a compressed kernel image. It is also possible to do ``make install`` if you have lilo installed to suit the kernel makefiles, but you may want to check your particular lilo setup first. @@ -332,85 +330,10 @@ Compiling the kernel If something goes wrong ----------------------- - - If you have problems that seem to be due to kernel bugs, please check - the file MAINTAINERS to see if there is a particular person associated - with the part of the kernel that you are having trouble with. If there - isn't anyone listed there, then the second best thing is to mail - them to me (torvalds@linux-foundation.org), and possibly to any other - relevant mailing-list or to the newsgroup. - - - In all bug-reports, *please* tell what kernel you are talking about, - how to duplicate the problem, and what your setup is (use your common - sense). If the problem is new, tell me so, and if the problem is - old, please try to tell me when you first noticed it. - - - If the bug results in a message like:: - - unable to handle kernel paging request at address C0000010 - Oops: 0002 - EIP: 0010:XXXXXXXX - eax: xxxxxxxx ebx: xxxxxxxx ecx: xxxxxxxx edx: xxxxxxxx - esi: xxxxxxxx edi: xxxxxxxx ebp: xxxxxxxx - ds: xxxx es: xxxx fs: xxxx gs: xxxx - Pid: xx, process nr: xx - xx xx xx xx xx xx xx xx xx xx - - or similar kernel debugging information on your screen or in your - system log, please duplicate it *exactly*. The dump may look - incomprehensible to you, but it does contain information that may - help debugging the problem. The text above the dump is also - important: it tells something about why the kernel dumped code (in - the above example, it's due to a bad kernel pointer). More information - on making sense of the dump is in Documentation/admin-guide/bug-hunting.rst - - - If you compiled the kernel with CONFIG_KALLSYMS you can send the dump - as is, otherwise you will have to use the ``ksymoops`` program to make - sense of the dump (but compiling with CONFIG_KALLSYMS is usually preferred). - This utility can be downloaded from - https://www.kernel.org/pub/linux/utils/kernel/ksymoops/ . - Alternatively, you can do the dump lookup by hand: - - - In debugging dumps like the above, it helps enormously if you can - look up what the EIP value means. The hex value as such doesn't help - me or anybody else very much: it will depend on your particular - kernel setup. What you should do is take the hex value from the EIP - line (ignore the ``0010:``), and look it up in the kernel namelist to - see which kernel function contains the offending address. - - To find out the kernel function name, you'll need to find the system - binary associated with the kernel that exhibited the symptom. This is - the file 'linux/vmlinux'. To extract the namelist and match it against - the EIP from the kernel crash, do:: - - nm vmlinux | sort | less - - This will give you a list of kernel addresses sorted in ascending - order, from which it is simple to find the function that contains the - offending address. Note that the address given by the kernel - debugging messages will not necessarily match exactly with the - function addresses (in fact, that is very unlikely), so you can't - just 'grep' the list: the list will, however, give you the starting - point of each kernel function, so by looking for the function that - has a starting address lower than the one you are searching for but - is followed by a function with a higher address you will find the one - you want. In fact, it may be a good idea to include a bit of - "context" in your problem report, giving a few lines around the - interesting one. - - If you for some reason cannot do the above (you have a pre-compiled - kernel image or similar), telling me as much about your setup as - possible will help. Please read - 'Documentation/admin-guide/reporting-issues.rst' for details. - - - Alternatively, you can use gdb on a running kernel. (read-only; i.e. you - cannot change values or set break points.) To do this, first compile the - kernel with -g; edit arch/x86/Makefile appropriately, then do a ``make - clean``. You'll also need to enable CONFIG_PROC_FS (via ``make config``). - - After you've rebooted with the new kernel, do ``gdb vmlinux /proc/kcore``. - You can now use all the usual gdb commands. The command to look up the - point where your system crashed is ``l *0xXXXXXXXX``. (Replace the XXXes - with the EIP value.) - - gdb'ing a non-running kernel currently fails because ``gdb`` (wrongly) - disregards the starting offset for which the kernel is compiled. +If you have problems that seem to be due to kernel bugs, please follow the +instructions at 'Documentation/admin-guide/reporting-issues.rst'. + +Hints on understanding kernel bug reports are in +'Documentation/admin-guide/bug-hunting.rst'. More on debugging the kernel +with gdb is in 'Documentation/dev-tools/gdb-kernel-debugging.rst' and +'Documentation/dev-tools/kgdb.rst'. |