Re: [PATCH bpf-next v2] bpf: fix segmentation fault of test_progs
From: Daniel Borkmann <daniel@iogearbox.net>
Date: 2020-08-11 13:20:13
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bpf, lkml
On 8/10/20 5:39 PM, Jianlin Lv wrote:
test_progs reports the segmentation fault as below $ sudo ./test_progs -t mmap --verbose test_mmap:PASS:skel_open_and_load 0 nsec ...... test_mmap:PASS:adv_mmap1 0 nsec test_mmap:PASS:adv_mmap2 0 nsec test_mmap:PASS:adv_mmap3 0 nsec test_mmap:PASS:adv_mmap4 0 nsec Segmentation fault This issue was triggered because mmap() and munmap() used inconsistent length parameters; mmap() creates a new mapping of 3*page_size, but the length parameter set in the subsequent re-map and munmap() functions is 4*page_size; this leads to the destruction of the process space. To fix this issue, first create 4 pages of anonymous mapping,then do all the mmap() with MAP_FIXED. Another issue is that when unmap the second page fails, the length parameter to delete tmp1 mappings should be 4*page_size. Signed-off-by: Jianlin Lv <redacted>
Applied, thanks!