On Tuesday 23 May 2017 08:22 AM, Hatayama, Daisuke wrote: > Currently, makedumpfile results in Segmentation fault on sadump dump > files as follows: > > # LANG=C makedumpfile -f --message-level=31 -ld31 -x vmlinux ./sadump_vmcore sadump_vmcore-ld31 > sadump: read dump device as single partition > sadump: single partition configuration > page_size : 4096 > sadump: timezone information is missing > Segmentation fault > > By bisect, I found that this issue is caused by the following commit > that moves invocation of cache_init() in initial() a bit early: > > # git bisect bad > 8e2834bac4f62da3894da297f083068431be6d80 is the first bad commit > commit 8e2834bac4f62da3894da297f083068431be6d80 > Author: Pratyush Anand <panand at redhat.com> > Date: Thu Mar 2 17:37:11 2017 +0900 > > [PATCH v3 2/7] initial(): call cache_init() a bit early > > Call cache_init() before get_kcore_dump_loads(), because latter uses > cache_search(). > > Call path is like this : > get_kcore_dump_loads() -> process_dump_load() -> vaddr_to_paddr() -> > vtop4_x86_64() -> readmem() -> cache_search() > > Signed-off-by: Pratyush Anand <panand at redhat.com> > > :100644 100644 6942047199deb09dd1fff2121e264584dbb05587 3b8e9810468de26b0d8b73d456f0bd4f3d3aa2fe M makedumpfile.c > > In this timing, on sadump vmcores, info->page_size has not been > initialized yet so has 0. So, malloc() in cache_init() returns a chunk > of 0 size. A bit later, info->page_size is initialized with 4096. > Later processing on cache.c behaves assuming the chunk size is 8 * > 4096. This destroys objects allocated after the chunk, resulting in > the above Segmentation fault. > > To fix this issue, this commit moves setting info->page_size before > cache_init(). > > Signed-off-by: HATAYAMA Daisuke <d.hatayama at jp.fujitsu.com> > Cc: Pratyush Anand <panand at redhat.com> For 1/2 Reviewed-by: Pratyush Anand <panand at redhat.com> > --- > makedumpfile.c | 6 +++--- > 1 file changed, 3 insertions(+), 3 deletions(-) > > diff --git a/makedumpfile.c b/makedumpfile.c > index 301772a..f300b19 100644 > --- a/makedumpfile.c > +++ b/makedumpfile.c > @@ -3878,6 +3878,9 @@ initial(void) > if (!get_value_for_old_linux()) > return FALSE; > > + if (info->flag_sadump && !set_page_size(sadump_page_size())) > + return FALSE; > + > if (!is_xen_memory() && !cache_init()) > return FALSE; > > @@ -3906,9 +3909,6 @@ initial(void) > return FALSE; > } > > - if (!set_page_size(sadump_page_size())) > - return FALSE; > - > if (!sadump_initialize_bitmap_memory()) > return FALSE; > >
