Revision 3cf6a32f3f2a45944dd5be5c6ac4deb46bcd3bee authored by Michael Petlan on 17 March 2022, 13:55:36 UTC, committed by Arnaldo Carvalho de Melo on 18 March 2022, 21:39:09 UTC
Before this patch, the symbol end address fixup to be called, needed two conditions being met: if (prev->end == prev->start && prev->end != curr->start) Where "prev->end == prev->start" means that prev is zero-long (and thus needs a fixup) and "prev->end != curr->start" means that fixup hasn't been applied yet However, this logic is incorrect in the following situation: *curr = {rb_node = {__rb_parent_color = 278218928, rb_right = 0x0, rb_left = 0x0}, start = 0xc000000000062354, end = 0xc000000000062354, namelen = 40, type = 2 '\002', binding = 0 '\000', idle = 0 '\000', ignore = 0 '\000', inlined = 0 '\000', arch_sym = 0 '\000', annotate2 = false, name = 0x1159739e "kprobe_optinsn_page\t[__builtin__kprobes]"} *prev = {rb_node = {__rb_parent_color = 278219041, rb_right = 0x109548b0, rb_left = 0x109547c0}, start = 0xc000000000062354, end = 0xc000000000062354, namelen = 12, type = 2 '\002', binding = 1 '\001', idle = 0 '\000', ignore = 0 '\000', inlined = 0 '\000', arch_sym = 0 '\000', annotate2 = false, name = 0x1095486e "optinsn_slot"} In this case, prev->start == prev->end == curr->start == curr->end, thus the condition above thinks that "we need a fixup due to zero length of prev symbol, but it has been probably done, since the prev->end == curr->start", which is wrong. After the patch, the execution path proceeds to arch__symbols__fixup_end function which fixes up the size of prev symbol by adding page_size to its end offset. Fixes: 3b01a413c196c910 ("perf symbols: Improve kallsyms symbol end addr calculation") Signed-off-by: Michael Petlan <mpetlan@redhat.com> Cc: Athira Jajeev <atrajeev@linux.vnet.ibm.com> Cc: Jiri Olsa <jolsa@kernel.org> Cc: Kajol Jain <kjain@linux.ibm.com> Cc: Madhavan Srinivasan <maddy@linux.ibm.com> Link: http://lore.kernel.org/lkml/20220317135536.805-1-mpetlan@redhat.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
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bpf_devel_QA.rst | -rw-r--r-- | 27.5 KB |
bpf_licensing.rst | -rw-r--r-- | 3.5 KB |
btf.rst | -rw-r--r-- | 33.3 KB |
classic_vs_extended.rst | -rw-r--r-- | 13.5 KB |
drgn.rst | -rw-r--r-- | 8.8 KB |
faq.rst | -rw-r--r-- | 220 bytes |
helpers.rst | -rw-r--r-- | 197 bytes |
index.rst | -rw-r--r-- | 744 bytes |
instruction-set.rst | -rw-r--r-- | 9.5 KB |
llvm_reloc.rst | -rw-r--r-- | 10.9 KB |
map_cgroup_storage.rst | -rw-r--r-- | 6.3 KB |
maps.rst | -rw-r--r-- | 1.4 KB |
other.rst | -rw-r--r-- | 73 bytes |
prog_cgroup_sockopt.rst | -rw-r--r-- | 4.0 KB |
prog_cgroup_sysctl.rst | -rw-r--r-- | 5.0 KB |
prog_flow_dissector.rst | -rw-r--r-- | 5.2 KB |
prog_lsm.rst | -rw-r--r-- | 4.5 KB |
prog_sk_lookup.rst | -rw-r--r-- | 3.8 KB |
programs.rst | -rw-r--r-- | 93 bytes |
ringbuf.rst | -rw-r--r-- | 11.0 KB |
s390.rst | -rw-r--r-- | 5.6 KB |
syscall_api.rst | -rw-r--r-- | 340 bytes |
test_debug.rst | -rw-r--r-- | 125 bytes |
verifier.rst | -rw-r--r-- | 19.2 KB |
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