Clang16 links the purgatory text in two sections:
[ 1] .text PROGBITS 0000000000000000 00000040
00000000000011a1 0000000000000000 AX 0 0 16
[ 2] .rela.text RELA 0000000000000000 00003498
0000000000000648 0000000000000018 I 24 1 8
...
[17] .text.hot. PROGBITS 0000000000000000 00003220
000000000000020b 0000000000000000 AX 0 0 1
[18] .rela.text.hot. RELA 0000000000000000 00004428
0000000000000078 0000000000000018 I 24 17 8
And both of them have their range [sh_addr ... sh_addr+sh_size] on the
area pointed by `e_entry`.
This causes that image->start is calculated twice, once for .text and
another time for .text.hot. The second calculation leaves image->start
in a random location.
Because of this, the system crashes inmediatly after:
kexec_core: Starting new kernel
Signed-off-by: Ricardo Ribalda <ribalda@xxxxxxxxxxxx>
---
kexec: Support purgatories with .text.hot sections
Clang16 links the purgatory text in two sections:
[ 1] .text PROGBITS 0000000000000000 00000040
00000000000011a1 0000000000000000 AX 0 0 16
[ 2] .rela.text RELA 0000000000000000 00003498
0000000000000648 0000000000000018 I 24 1 8
...
[17] .text.hot. PROGBITS 0000000000000000 00003220
000000000000020b 0000000000000000 AX 0 0 1
[18] .rela.text.hot. RELA 0000000000000000 00004428
0000000000000078 0000000000000018 I 24 17 8
And both of them have their range [sh_addr ... sh_addr+sh_size] on the
area pointed by `e_entry`.
This causes that image->start is calculated twice, once for .text and
another time for .text.hot. The second calculation leaves image->start
in a random location.
Because of this, the system crashes inmediatly after:
kexec_core: Starting new kernel
To: Eric Biederman <ebiederm@xxxxxxxxxxxx>
Cc: Philipp Rudo <prudo@xxxxxxxxxxxxxxxxxx>
Cc: kexec@xxxxxxxxxxxxxxxxxxx
Cc: linux-kernel@xxxxxxxxxxxxxxx
---
kernel/kexec_file.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/kernel/kexec_file.c b/kernel/kexec_file.c
index f1a0e4e3fb5c..b1a25d97d5e2 100644
--- a/kernel/kexec_file.c
+++ b/kernel/kexec_file.c
@@ -904,7 +904,8 @@ static int kexec_purgatory_setup_sechdrs(struct purgatory_info *pi,
if (sechdrs[i].sh_flags & SHF_EXECINSTR &&
pi->ehdr->e_entry >= sechdrs[i].sh_addr &&
pi->ehdr->e_entry < (sechdrs[i].sh_addr
- + sechdrs[i].sh_size)) {
+ + sechdrs[i].sh_size) &&
+ kbuf->image->start != pi->ehdr->e_shnum) {
kbuf->image->start -= sechdrs[i].sh_addr;
kbuf->image->start += kbuf->mem + offset;
}
---
base-commit: 17214b70a159c6547df9ae204a6275d983146f6b
change-id: 20230321-kexec_clang16-4510c23d129c
Best regards,
--
Ricardo Ribalda <ribalda@xxxxxxxxxxxx>
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