From: Ricardo Ribalda <ribalda@chromium.org> To: Eric Biederman <ebiederm@xmission.com> Cc: Philipp Rudo <prudo@linux.vnet.ibm.com>, Ricardo Ribalda <ribalda@chromium.org>, linux-kernel@vger.kernel.org, kexec@lists.infradead.org Subject: [PATCH] kexec: Support purgatories with .text.hot sections Date: Tue, 21 Mar 2023 12:49:08 +0100 [thread overview] Message-ID: <20230321-kexec_clang16-v1-0-a768fc2c7c4d@chromium.org> (raw) 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@chromium.org> --- 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@xmission.com> Cc: Philipp Rudo <prudo@linux.vnet.ibm.com> Cc: kexec@lists.infradead.org Cc: linux-kernel@vger.kernel.org --- 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@chromium.org>
WARNING: multiple messages have this Message-ID (diff)
From: Ricardo Ribalda <ribalda@chromium.org> To: Eric Biederman <ebiederm@xmission.com> Cc: Philipp Rudo <prudo@linux.vnet.ibm.com>, Ricardo Ribalda <ribalda@chromium.org>, linux-kernel@vger.kernel.org, kexec@lists.infradead.org Subject: [PATCH] kexec: Support purgatories with .text.hot sections Date: Tue, 21 Mar 2023 12:49:08 +0100 [thread overview] Message-ID: <20230321-kexec_clang16-v1-0-a768fc2c7c4d@chromium.org> (raw) 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@chromium.org> --- 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@xmission.com> Cc: Philipp Rudo <prudo@linux.vnet.ibm.com> Cc: kexec@lists.infradead.org Cc: linux-kernel@vger.kernel.org --- 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@chromium.org> _______________________________________________ kexec mailing list kexec@lists.infradead.org http://lists.infradead.org/mailman/listinfo/kexec
next reply other threads:[~2023-03-21 11:49 UTC|newest] Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top 2023-03-21 11:49 Ricardo Ribalda [this message] 2023-03-21 11:49 ` [PATCH] kexec: Support purgatories with .text.hot sections Ricardo Ribalda 2023-03-22 14:34 ` Steven Rostedt 2023-03-22 14:34 ` Steven Rostedt 2023-03-22 14:42 ` Ricardo Ribalda 2023-03-22 14:42 ` Ricardo Ribalda 2023-03-22 14:52 ` Baoquan He 2023-03-22 14:52 ` Baoquan He 2023-03-22 15:00 ` Steven Rostedt 2023-03-22 15:00 ` Steven Rostedt 2023-03-23 0:17 ` Baoquan He 2023-03-23 0:17 ` Baoquan He 2023-03-22 20:13 ` Ross Zwisler 2023-03-22 20:13 ` Ross Zwisler
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