create-diff-object: Fix out of range relocation verification check #1493
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kpatch_check_relocations() validates relocation targets using sec->data->d_size, which doesnt reflect entire section size. Sections such as __bug_table may be represented by multiple records. In this case, data->d_size is lesser than the logical section size, leading to false out-of-range relocation errors. ERROR: kernel/fork.o: kpatch_check_relocations: .text.kernel_clone+0x2f6: out-of-range relocation __bug_table+0x1b2 sec_off: 432 sec_size: 48 The correct size of the section is sec->sh.sh_size, total size of __bug_table (480 bytes, corresponding to 30 struct bug_entry records). Fix this by using sec->sh.sh_size instead of sec->data->d_size when verifying relocation bounds. Additionally, ensure that newly rebuilt .kpatch.strings sections update sh.sh_size after the string table is finalized. Without this update, kpatch may fail with: ERROR: kernel/fork.o: kpatch_check_relocations: .kpatch.funcs+0x28: out-of-range relocation .kpatch.strings+0x8 sec_off: 8 sec_size: 0 Signed-off-by: Sumanth Korikkar <sumanthk@linux.ibm.com>
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kpatch_check_relocations() validates relocation targets using sec->data->d_size, which doesnt reflect entire section size.
Sections such as __bug_table may be represented by multiple records. In this case, data->d_size is lesser than the logical section size, leading to false out-of-range relocation errors.
ERROR: kernel/fork.o: kpatch_check_relocations:
.text.kernel_clone+0x2f6: out-of-range relocation __bug_table+0x1b2
sec_off: 432 sec_size: 48
The correct size of the section is sec->sh.sh_size, total size of __bug_table (480 bytes, corresponding to 30 struct bug_entry records).
Fix this by using sec->sh.sh_size instead of sec->data->d_size when verifying relocation bounds.
Additionally, ensure that newly rebuilt .kpatch.strings sections update sh.sh_size after the string table is finalized. Without this update, kpatch may fail with:
ERROR: kernel/fork.o: kpatch_check_relocations:
.kpatch.funcs+0x28: out-of-range relocation .kpatch.strings+0x8
sec_off: 8 sec_size: 0