18447dba2b
It introduces four patches about aligning PT_LOAD segments and update to glibc-2.28-225.0.2.el8. Signed-off-by: Rongwei Wang <rongwei.wang@linux.alibaba.com>
137 lines
5.1 KiB
Diff
137 lines
5.1 KiB
Diff
From fe5893121176136b0ae3a5f9198536feeb6f64f8 Mon Sep 17 00:00:00 2001
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From: Rongwei Wang <rongwei.wang@linux.alibaba.com>
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Date: Wed, 19 Jul 2023 23:05:39 +0800
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Subject: [PATCH 2/6] elf: Properly align PT_LOAD segments [BZ #28676]
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When PT_LOAD segment alignment > the page size, allocate enough space to
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ensure that the segment can be properly aligned. This change helps code
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segments use huge pages become simple and available.
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This fixes [BZ #28676].
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Backport from master commit: 718fdd8
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Signed-off-by: Xu Yu <xuyu@linux.alibaba.com>
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Signed-off-by: Rongwei Wang <rongwei.wang@linux.alibaba.com>
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---
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elf/dl-load.c | 2 ++
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elf/dl-load.h | 3 ++-
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elf/dl-map-segments.h | 50 +++++++++++++++++++++++++++++++++++++++----
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3 files changed, 50 insertions(+), 5 deletions(-)
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diff --git a/elf/dl-load.c b/elf/dl-load.c
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index 0b45e6e3..132e4233 100644
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--- a/elf/dl-load.c
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+++ b/elf/dl-load.c
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@@ -1,5 +1,6 @@
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/* Map in a shared object's segments from the file.
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Copyright (C) 1995-2018 Free Software Foundation, Inc.
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+ Copyright The GNU Toolchain Authors.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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@@ -1076,6 +1077,7 @@ _dl_map_object_from_fd (const char *name, const char *origname, int fd,
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c->mapend = ALIGN_UP (ph->p_vaddr + ph->p_filesz, GLRO(dl_pagesize));
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c->dataend = ph->p_vaddr + ph->p_filesz;
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c->allocend = ph->p_vaddr + ph->p_memsz;
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+ c->mapalign = ph->p_align;
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c->mapoff = ALIGN_DOWN (ph->p_offset, GLRO(dl_pagesize));
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/* Determine whether there is a gap between the last segment
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diff --git a/elf/dl-load.h b/elf/dl-load.h
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index 66ea2e92..d9f648ea 100644
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--- a/elf/dl-load.h
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+++ b/elf/dl-load.h
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@@ -1,5 +1,6 @@
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/* Map in a shared object's segments from the file.
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Copyright (C) 1995-2018 Free Software Foundation, Inc.
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+ Copyright The GNU Toolchain Authors.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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@@ -74,7 +75,7 @@ ELF_PREFERRED_ADDRESS_DATA;
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Its details have been expanded out and converted. */
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struct loadcmd
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{
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- ElfW(Addr) mapstart, mapend, dataend, allocend;
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+ ElfW(Addr) mapstart, mapend, dataend, allocend, mapalign;
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ElfW(Off) mapoff;
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int prot; /* PROT_* bits. */
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};
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diff --git a/elf/dl-map-segments.h b/elf/dl-map-segments.h
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index 084076a2..61ba04cd 100644
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--- a/elf/dl-map-segments.h
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+++ b/elf/dl-map-segments.h
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@@ -1,5 +1,6 @@
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/* Map in a shared object's segments. Generic version.
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Copyright (C) 1995-2018 Free Software Foundation, Inc.
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+ Copyright The GNU Toolchain Authors.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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@@ -18,6 +19,50 @@
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#include <dl-load.h>
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+/* Map a segment and align it properly. */
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+
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+static __always_inline ElfW(Addr)
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+_dl_map_segment (const struct loadcmd *c, ElfW(Addr) mappref,
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+ const size_t maplength, int fd)
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+{
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+ if (__glibc_likely (c->mapalign <= GLRO(dl_pagesize)))
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+ return (ElfW(Addr)) __mmap ((void *) mappref, maplength, c->prot,
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+ MAP_COPY|MAP_FILE, fd, c->mapoff);
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+
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+ /* If the segment alignment > the page size, allocate enough space to
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+ ensure that the segment can be properly aligned. */
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+ ElfW(Addr) maplen = (maplength >= c->mapalign
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+ ? (maplength + c->mapalign)
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+ : (2 * c->mapalign));
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+ ElfW(Addr) map_start = (ElfW(Addr)) __mmap ((void *) mappref, maplen,
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+ PROT_NONE,
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+ MAP_ANONYMOUS|MAP_PRIVATE,
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+ -1, 0);
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+ if (__glibc_unlikely ((void *) map_start == MAP_FAILED))
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+ return map_start;
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+
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+ ElfW(Addr) map_start_aligned = ALIGN_UP (map_start, c->mapalign);
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+ map_start_aligned = (ElfW(Addr)) __mmap ((void *) map_start_aligned,
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+ maplength, c->prot,
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+ MAP_COPY|MAP_FILE|MAP_FIXED,
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+ fd, c->mapoff);
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+ if (__glibc_unlikely ((void *) map_start_aligned == MAP_FAILED))
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+ __munmap ((void *) map_start, maplen);
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+ else
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+ {
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+ /* Unmap the unused regions. */
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+ ElfW(Addr) delta = map_start_aligned - map_start;
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+ if (delta)
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+ __munmap ((void *) map_start, delta);
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+ ElfW(Addr) map_end = map_start_aligned + maplength;
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+ delta = map_start + maplen - map_end;
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+ if (delta)
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+ __munmap ((void *) map_end, delta);
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+ }
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+
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+ return map_start_aligned;
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+}
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+
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/* This implementation assumes (as does the corresponding implementation
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of _dl_unmap_segments, in dl-unmap-segments.h) that shared objects
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are always laid out with all segments contiguous (or with gaps
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@@ -53,10 +98,7 @@ _dl_map_segments (struct link_map *l, int fd,
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- MAP_BASE_ADDR (l));
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/* Remember which part of the address space this object uses. */
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- l->l_map_start = (ElfW(Addr)) __mmap ((void *) mappref, maplength,
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- c->prot,
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- MAP_COPY|MAP_FILE,
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- fd, c->mapoff);
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+ l->l_map_start = _dl_map_segment (c, mappref, maplength, fd);
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if (__glibc_unlikely ((void *) l->l_map_start == MAP_FAILED))
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return DL_MAP_SEGMENTS_ERROR_MAP_SEGMENT;
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--
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2.27.0
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