path: root/mm
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authorLinus Torvalds <torvalds@linux-foundation.org>2020-02-21 16:03:36 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2020-02-21 16:03:36 -0800
commit63f01d852c75366fb4d15ce217d12c48b69a4bcc (patch)
tree8d47f51afb6763b923fc3082f6a259456a2c77f7 /mm
parentMerge tag 'powerpc-5.6-3' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux (diff)
parentmm: Avoid creating virtual address aliases in brk()/mmap()/mremap() (diff)
Merge tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux
Pull arm64 fixes from Will Deacon: "It's all straightforward apart from the changes to mmap()/mremap() in relation to their handling of address arguments from userspace with non-zero tag bits in the upper byte. The change to brk() is necessary to fix a nasty user-visible regression in malloc(), but we tightened up mmap() and mremap() at the same time because they also allow the user to create virtual aliases by accident. It's much less likely than brk() to matter in practice, but enforcing the principle of "don't permit the creation of mappings using tagged addresses" leads to a straightforward ABI without having to worry about the "but what if a crazy program did foo?" aspect of things. Summary: - Fix regression in malloc() caused by ignored address tags in brk() - Add missing brackets around argument to untagged_addr() macro - Fix clang build when using binutils assembler - Fix silly typo in virtual memory map documentation" * tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux: mm: Avoid creating virtual address aliases in brk()/mmap()/mremap() docs: arm64: fix trivial spelling enought to enough in memory.rst arm64: memory: Add missing brackets to untagged_addr() macro arm64: lse: Fix LSE atomics with LLVM
Diffstat (limited to 'mm')
2 files changed, 0 insertions, 5 deletions
diff --git a/mm/mmap.c b/mm/mmap.c
index 6756b8bb0033..d681a20eb4ea 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -195,8 +195,6 @@ SYSCALL_DEFINE1(brk, unsigned long, brk)
bool downgraded = false;
- brk = untagged_addr(brk);
if (down_write_killable(&mm->mmap_sem))
return -EINTR;
@@ -1557,8 +1555,6 @@ unsigned long ksys_mmap_pgoff(unsigned long addr, unsigned long len,
struct file *file = NULL;
unsigned long retval;
- addr = untagged_addr(addr);
if (!(flags & MAP_ANONYMOUS)) {
audit_mmap_fd(fd, flags);
file = fget(fd);
diff --git a/mm/mremap.c b/mm/mremap.c
index 122938dcec15..af363063ea23 100644
--- a/mm/mremap.c
+++ b/mm/mremap.c
@@ -607,7 +607,6 @@ SYSCALL_DEFINE5(mremap, unsigned long, addr, unsigned long, old_len,
addr = untagged_addr(addr);
- new_addr = untagged_addr(new_addr);
return ret;