linux/fs/proc/vmcore.c, branch v3.4.19

fadump: Introduce cleanup routine to invalidate /proc/vmcore.

2012-02-22T23:50:02Z

With the firmware-assisted dump support we don't require a reboot when we are in second kernel after crash. The second kernel after crash is a normal kernel boot and has knowledge about entire system RAM with the page tables initialized for entire system RAM. Hence once the dump is saved to disk, we can just release the reserved memory area for general use and continue with second kernel as production kernel. Hence when we release the reserved memory that contains dump data, the '/proc/vmcore' will not be valid anymore. Hence this patch introduces a cleanup routine that invalidates and removes the /proc/vmcore file. This routine will be invoked before we release the reserved dump memory area. Signed-off-by: Mahesh Salgaonkar Signed-off-by: Benjamin Herrenschmidt

fs: add export.h to files using EXPORT_SYMBOL/THIS_MODULE macros

2011-10-31T23:30:31Z

These files were getting via an implicit include path, but we want to crush those out of existence since they cost time during compiles of processing thousands of lines of headers for no reason. Give them the lightweight header that just contains the EXPORT_SYMBOL infrastructure. Signed-off-by: Paul Gortmaker

fs/proc/vmcore.c: add hook to read_from_oldmem() to check for non-ram pages

2011-05-27T00:12:37Z

The balloon driver in a Xen guest frees guest pages and marks them as mmio. When the kernel crashes and the crash kernel attempts to read the oldmem via /proc/vmcore a read from ballooned pages will generate 100% load in dom0 because Xen asks qemu-dm for the page content. Since the reads come in as 8byte requests each ballooned page is tried 512 times. With this change a hook can be registered which checks wether the given pfn is really ram. The hook has to return a value > 0 for ram pages, a value < 0 on error (because the hypercall is not known) and 0 for non-ram pages. This will reduce the time to read /proc/vmcore. Without this change a 512M guest with 128M crashkernel region needs 200 seconds to read it, with this change it takes just 2 seconds. Signed-off-by: Olaf Hering Cc: Alexey Dobriyan Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

ARM: 6485/5: proc/vmcore - allow archs to override vmcore_elf_check_arch()

2010-11-30T13:39:55Z

Allow architectures to redefine this macro if needed. This is useful for example in architectures where 64-bit ELF vmcores are not supported. Specifying zero vmcore_elf64_check_arch() allows compiler to optimize away unnecessary parts of parse_crash_elf64_headers(). We also rename the macro to vmcore_elf64_check_arch() to reflect that it is used for 64-bit vmcores only. Signed-off-by: Mika Westerberg Signed-off-by: Russell King

/proc/vmcore: fix seeking

2010-09-23T00:22:38Z

Commit 73296bc611 ("procfs: Use generic_file_llseek in /proc/vmcore") broke seeking on /proc/vmcore. This changes it back to use default_llseek in order to restore the original behaviour. The problem with generic_file_llseek is that it only allows seeks up to inode->i_sb->s_maxbytes, which is zero on procfs and some other virtual file systems. We should merge generic_file_llseek and default_llseek some day and clean this up in a proper way, but for 2.6.35/36, reverting vmcore is the safer solution. Signed-off-by: Arnd Bergmann Cc: Frederic Weisbecker Reported-by: CAI Qian Tested-by: CAI Qian Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

Merge branch 'bkl/procfs' of git://git.kernel.org/pub/scm/linux/kernel/git/frederic/random-tracing

2010-05-20T00:23:28Z

* 'bkl/procfs' of git://git.kernel.org/pub/scm/linux/kernel/git/frederic/random-tracing: sunrpc: Include missing smp_lock.h procfs: Kill the bkl in ioctl procfs: Push down the bkl from ioctl procfs: Use generic_file_llseek in /proc/vmcore procfs: Use generic_file_llseek in /proc/kmsg procfs: Use generic_file_llseek in /proc/kcore procfs: Kill BKL in llseek on proc base

procfs: Use generic_file_llseek in /proc/vmcore

2010-04-09T15:23:24Z

/proc/vmcore has no llseek and then falls down to use default_llseek. This is racy against read_vmcore() that directly manipulates fpos but it doesn't hold the bkl there so using it in llseek doesn't protect anything. Let's use generic_file_llseek() instead. Signed-off-by: Frederic Weisbecker Acked-by: Arnd Bergmann Cc: Thomas Gleixner Cc: Andrew Morton Cc: Ingo Molnar Cc: John Kacur Cc: KAMEZAWA Hiroyuki Cc: Al Viro

include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h

2010-03-30T13:02:32Z

percpu.h is included by sched.h and module.h and thus ends up being included when building most .c files. percpu.h includes slab.h which in turn includes gfp.h making everything defined by the two files universally available and complicating inclusion dependencies. percpu.h -> slab.h dependency is about to be removed. Prepare for this change by updating users of gfp and slab facilities include those headers directly instead of assuming availability. As this conversion needs to touch large number of source files, the following script is used as the basis of conversion. http://userweb.kernel.org/~tj/misc/slabh-sweep.py The script does the followings. * Scan files for gfp and slab usages and update includes such that only the necessary includes are there. ie. if only gfp is used, gfp.h, if slab is used, slab.h. * When the script inserts a new include, it looks at the include blocks and try to put the new include such that its order conforms to its surrounding. It's put in the include block which contains core kernel includes, in the same order that the rest are ordered - alphabetical, Christmas tree, rev-Xmas-tree or at the end if there doesn't seem to be any matching order. * If the script can't find a place to put a new include (mostly because the file doesn't have fitting include block), it prints out an error message indicating which .h file needs to be added to the file. The conversion was done in the following steps. 1. The initial automatic conversion of all .c files updated slightly over 4000 files, deleting around 700 includes and adding ~480 gfp.h and ~3000 slab.h inclusions. The script emitted errors for ~400 files. 2. Each error was manually checked. Some didn't need the inclusion, some needed manual addition while adding it to implementation .h or embedding .c file was more appropriate for others. This step added inclusions to around 150 files. 3. The script was run again and the output was compared to the edits from #2 to make sure no file was left behind. 4. Several build tests were done and a couple of problems were fixed. e.g. lib/decompress_*.c used malloc/free() wrappers around slab APIs requiring slab.h to be added manually. 5. The script was run on all .h files but without automatically editing them as sprinkling gfp.h and slab.h inclusions around .h files could easily lead to inclusion dependency hell. Most gfp.h inclusion directives were ignored as stuff from gfp.h was usually wildly available and often used in preprocessor macros. Each slab.h inclusion directive was examined and added manually as necessary. 6. percpu.h was updated not to include slab.h. 7. Build test were done on the following configurations and failures were fixed. CONFIG_GCOV_KERNEL was turned off for all tests (as my distributed build env didn't work with gcov compiles) and a few more options had to be turned off depending on archs to make things build (like ipr on powerpc/64 which failed due to missing writeq). * x86 and x86_64 UP and SMP allmodconfig and a custom test config. * powerpc and powerpc64 SMP allmodconfig * sparc and sparc64 SMP allmodconfig * ia64 SMP allmodconfig * s390 SMP allmodconfig * alpha SMP allmodconfig * um on x86_64 SMP allmodconfig 8. percpu.h modifications were reverted so that it could be applied as a separate patch and serve as bisection point. Given the fact that I had only a couple of failures from tests on step 6, I'm fairly confident about the coverage of this conversion patch. If there is a breakage, it's likely to be something in one of the arch headers which should be easily discoverable easily on most builds of the specific arch. Signed-off-by: Tejun Heo Guess-its-ok-by: Christoph Lameter Cc: Ingo Molnar Cc: Lee Schermerhorn

proc: vmcore - use kzalloc in get_new_element()

2009-06-18T20:03:41Z

Instead of kmalloc+memset better use straight kzalloc Signed-off-by: Cyrill Gorcunov Reviewed-by: WANG Cong Acked-by: Vivek Goyal Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

vmcore: remove saved_max_pfn check

2009-01-08T16:31:14Z

Remove the saved_max_pfn check from the /proc/vmcore function read_from_oldmem(). No need to verify, we should be able to just trust that "elfcorehdr=" is correctly passed to the crash kernel on the kernel command line like we do with other parameters. The read_from_oldmem() function in fs/proc/vmcore.c is quite similar to read_from_oldmem() in drivers/char/mem.c, but only in the latter it makes sense to use saved_max_pfn. For oldmem it is used to determine when to stop reading. For vmcore we already have the elf header info pointing out the physical memory regions, no need to pass the end-of- old-memory twice. Removing the saved_max_pfn check from vmcore makes it possible for architectures to skip oldmem but still support crash dump through vmcore - without the need for the old saved_max_pfn cruft. Architectures that want to play safe can do the saved_max_pfn check in copy_oldmem_page(). Not sure why anyone would want to do that, but that's even safer than today - the saved_max_pfn check in vmcore removed by this patch only checks the first page. Signed-off-by: Magnus Damm Acked-by: Vivek Goyal Acked-by: Simon Horman Cc: "Eric W. Biederman" Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds