From 90cc28fc9ab0a0076bcd9120b4f791401655280d Mon Sep 17 00:00:00 2001 Message-Id: <90cc28fc9ab0a0076bcd9120b4f791401655280d.1496033260.git.panand@redhat.com> In-Reply-To: <302c16ede3723264ca0abb5eef9c9f553ffcfbd7.1496033260.git.panand@redhat.com> References: <302c16ede3723264ca0abb5eef9c9f553ffcfbd7.1496033260.git.panand@redhat.com> From: "Hatayama, Daisuke" Date: Tue, 23 May 2017 02:52:51 +0000 Subject: [PATCH 3/3] sadump: set info->page_size before cache_init() 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 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 :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 Cc: Pratyush Anand --- makedumpfile.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/makedumpfile-1.6.1/makedumpfile.c b/makedumpfile-1.6.1/makedumpfile.c index 9babf1a07154..2e4286c83b8f 100644 --- a/makedumpfile-1.6.1/makedumpfile.c +++ b/makedumpfile-1.6.1/makedumpfile.c @@ -3921,6 +3921,9 @@ 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; @@ -3949,9 +3952,6 @@ initial(void) return FALSE; } - if (!set_page_size(sadump_page_size())) - return FALSE; - if (!sadump_initialize_bitmap_memory()) return FALSE; -- 2.9.3