kexec_load_purgatory() derives image->start by locating e_entry inside an
SHF_EXECINSTR section. If the purgatory object contains multiple executable
sections with overlapping sh_addr, the entrypoint check can match more than
once and trigger a WARN.
Derive the entry section from the purgatory_start symbol when present and
compute image->start from its final placement. Keep the existing e_entry
fallback for purgatories that do not expose the symbol.
WARNING: kernel/kexec_file.c:1009 at kexec_load_purgatory+0x395/0x3c0, CPU#10:
kexec/1784
Call Trace:
<TASK>
bzImage64_load+0x133/0xa00
__do_sys_kexec_file_load+0x2b3/0x5c0
do_syscall_64+0x81/0x610
entry_SYSCALL_64_after_hwframe+0x76/0x7e
Fixes: 8652d44f466a ("kexec: support purgatories with .text.hot sections")
Signed-off-by: Li Chen <[email protected]>
---
kernel/kexec_file.c | 24 ++++++++++++++++++++++--
1 file changed, 22 insertions(+), 2 deletions(-)
diff --git a/kernel/kexec_file.c b/kernel/kexec_file.c
index 3f1d6c4e8ff2..d3c68c6b4bbc 100644
--- a/kernel/kexec_file.c
+++ b/kernel/kexec_file.c
@@ -880,6 +880,8 @@ static int kexec_calculate_store_digests(struct kimage
*image)
}
#ifdef CONFIG_ARCH_SUPPORTS_KEXEC_PURGATORY
+static const Elf_Sym * kexec_purgatory_find_symbol(struct purgatory_info *pi,
+ const char *name);
/*
* kexec_purgatory_setup_kbuf - prepare buffer to load purgatory.
* @pi: Purgatory to be loaded.
@@ -958,6 +960,10 @@ static int kexec_purgatory_setup_sechdrs(struct
purgatory_info *pi,
unsigned long offset;
size_t sechdrs_size;
Elf_Shdr *sechdrs;
+ const Elf_Sym *entry_sym;
+ u16 entry_shndx = 0;
+ unsigned long entry_off = 0;
+ bool start_fixed = false;
int i;
/*
@@ -975,6 +981,12 @@ static int kexec_purgatory_setup_sechdrs(struct
purgatory_info *pi,
bss_addr = kbuf->mem + kbuf->bufsz;
kbuf->image->start = pi->ehdr->e_entry;
+ entry_sym = kexec_purgatory_find_symbol(pi, "purgatory_start");
+ if (entry_sym) {
+ entry_shndx = entry_sym->st_shndx;
+ entry_off = entry_sym->st_value;
+ }
+
for (i = 0; i < pi->ehdr->e_shnum; i++) {
unsigned long align;
void *src, *dst;
@@ -992,6 +1004,13 @@ static int kexec_purgatory_setup_sechdrs(struct
purgatory_info *pi,
offset = ALIGN(offset, align);
+ if (!start_fixed && entry_sym && i == entry_shndx &&
+ (sechdrs[i].sh_flags & SHF_EXECINSTR) &&
+ entry_off < sechdrs[i].sh_size) {
+ kbuf->image->start = kbuf->mem + offset + entry_off;
+ start_fixed = true;
+ }
+
/*
* Check if the segment contains the entry point, if so,
* calculate the value of image->start based on it.
@@ -1002,13 +1021,14 @@ static int kexec_purgatory_setup_sechdrs(struct
purgatory_info *pi,
* is not set to the initial value, and warn the user so they
* have a chance to fix their purgatory's linker script.
*/
- if (sechdrs[i].sh_flags & SHF_EXECINSTR &&
+ if (!start_fixed && 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) &&
- !WARN_ON(kbuf->image->start != pi->ehdr->e_entry)) {
+ kbuf->image->start == pi->ehdr->e_entry) {
kbuf->image->start -= sechdrs[i].sh_addr;
kbuf->image->start += kbuf->mem + offset;
+ start_fixed = true;
}
src = (void *)pi->ehdr + sechdrs[i].sh_offset;
--
2.52.0
