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| author | David Gow <davidgow@google.com> | 2020-03-05 10:39:39 -0800 |
|---|---|---|
| committer | Richard Weinberger <richard@nod.at> | 2020-03-29 23:21:29 +0200 |
| commit | 598f5630361397c542a0ba2bec0ac5c0e1723d5c (patch) | |
| tree | 3ded48a12c36cb047ff59d8f21ea27e6532aca53 | |
| parent | 73343392aae8bdd939ca58e855889d1b015b0ef4 (diff) | |
| download | lwn-598f5630361397c542a0ba2bec0ac5c0e1723d5c.tar.gz lwn-598f5630361397c542a0ba2bec0ac5c0e1723d5c.zip | |
um: Fix overlapping ELF segments when statically linked
When statically linked, the .text section in UML kernels is not page
aligned, causing it to share a page with the executable headers. As
.text and the executable headers have different permissions, this causes
the kernel to wish to map the same page twice (once as headers with r--
permissions, once as .text with r-x permissions), causing a segfault,
and a nasty message printed to the host kernel's dmesg:
"Uhuuh, elf segment at 0000000060000000 requested but the memory is
mapped already"
By aligning the .text to a page boundary (as in the dynamically linked
version in dyn.lds.S), there is no such overlap, and the kernel runs
correctly.
Signed-off-by: David Gow <davidgow@google.com>
Reviewed-by: Brendan Higgins <brendanhiggins@google.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
| -rw-r--r-- | arch/um/kernel/uml.lds.S | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/um/kernel/uml.lds.S b/arch/um/kernel/uml.lds.S index 9f21443be2c9..3b6dab3d4501 100644 --- a/arch/um/kernel/uml.lds.S +++ b/arch/um/kernel/uml.lds.S @@ -19,10 +19,10 @@ SECTIONS __binary_start = START; . = START + SIZEOF_HEADERS; + . = ALIGN(PAGE_SIZE); _text = .; INIT_TEXT_SECTION(0) - . = ALIGN(PAGE_SIZE); .text : { |