From: David Hildenbrand <david@redhat.com>
To: linux-kernel@vger.kernel.org
Cc: David Hildenbrand <david@redhat.com>,
Andrew Morton <akpm@linux-foundation.org>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
"H. Peter Anvin" <hpa@zytor.com>,
Alexander Viro <viro@zeniv.linux.org.uk>,
Alexey Dobriyan <adobriyan@gmail.com>,
Steven Rostedt <rostedt@goodmis.org>,
Peter Zijlstra <peterz@infradead.org>,
Arnaldo Carvalho de Melo <acme@kernel.org>,
Mark Rutland <mark.rutland@arm.com>,
Alexander Shishkin <alexander.shishkin@linux.intel.com>,
Jiri Olsa <jolsa@redhat.com>, Namhyung Kim <namhyung@kernel.org>,
Petr Mladek <pmladek@suse.com>,
Sergey Senozhatsky <sergey.senozhatsky@gmail.com>,
Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
Rasmus Villemoes <linux@rasmusvillemoes.dk>,
Kees Cook <keescook@chromium.org>,
"Eric W. Biederman" <ebiederm@xmission.com>,
Greg Ungerer <gerg@linux-m68k.org>,
Geert Uytterhoeven <geert@linux-m68k.org>,
Mike Rapoport <rppt@kernel.org>, Vlastimil Babka <vbabka@suse.cz>,
Vincenzo Frascino <vincenzo.frascino@arm.com>,
Chinwen Chang <chinwen.chang@mediatek.com>,
Michel Lespinasse <walken@google.com>,
Catalin Marinas <catalin.marinas@arm.com>,
"Matthew Wilcox (Oracle)" <willy@infradead.org>,
Huang Ying <ying.huang@intel.com>, Jann Horn <jannh@google.com>,
Feng Tang <feng.tang@intel.com>,
Kevin Brodsky <Kevin.Brodsky@arm.com>,
Michael Ellerman <mpe@ellerman.id.au>,
Shawn Anastasio <shawn@anastas.io>,
Steven Price <steven.price@arm.com>,
Nicholas Piggin <npiggin@gmail.com>,
Christian Brauner <christian.brauner@ubuntu.com>,
Jens Axboe <axboe@kernel.dk>,
Gabriel Krisman Bertazi <krisman@collabora.com>,
Peter Xu <peterx@redhat.com>,
Suren Baghdasaryan <surenb@google.com>,
Shakeel Butt <shakeelb@google.com>,
Marco Elver <elver@google.com>,
Daniel Jordan <daniel.m.jordan@oracle.com>,
Nicolas Viennot <Nicolas.Viennot@twosigma.com>,
Thomas Cedeno <thomascedeno@google.com>,
Collin Fijalkovich <cfijalkovich@google.com>,
Michal Hocko <mhocko@suse.com>,
linux-api@vger.kernel.org, x86@kernel.org,
linux-fsdevel@vger.kernel.org, linux-mm@kvack.org
Subject: [PATCH RFC 5/7] mm: remove VM_DENYWRITE
Date: Fri, 23 Apr 2021 15:16:38 +0200 [thread overview]
Message-ID: <20210423131640.20080-6-david@redhat.com> (raw)
In-Reply-To: <20210423131640.20080-1-david@redhat.com>
All in-tree users of MAP_DENYWRITE are gone. MAP_DENYWRITE cannot be
set from user space, so all users are gone; let's remove it.
Signed-off-by: David Hildenbrand <david@redhat.com>
---
fs/proc/task_mmu.c | 1 -
include/linux/mm.h | 1 -
include/linux/mman.h | 1 -
include/trace/events/mmflags.h | 1 -
kernel/events/core.c | 2 --
kernel/fork.c | 3 ---
lib/test_printf.c | 5 ++---
mm/mmap.c | 27 +++------------------------
8 files changed, 5 insertions(+), 36 deletions(-)
diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
index e862cab69583..2710703c39b0 100644
--- a/fs/proc/task_mmu.c
+++ b/fs/proc/task_mmu.c
@@ -621,7 +621,6 @@ static void show_smap_vma_flags(struct seq_file *m, struct vm_area_struct *vma)
[ilog2(VM_MAYSHARE)] = "ms",
[ilog2(VM_GROWSDOWN)] = "gd",
[ilog2(VM_PFNMAP)] = "pf",
- [ilog2(VM_DENYWRITE)] = "dw",
[ilog2(VM_LOCKED)] = "lo",
[ilog2(VM_IO)] = "io",
[ilog2(VM_SEQ_READ)] = "sr",
diff --git a/include/linux/mm.h b/include/linux/mm.h
index 043702972e5f..cdad125af9fa 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -274,7 +274,6 @@ extern unsigned int kobjsize(const void *objp);
#define VM_GROWSDOWN 0x00000100 /* general info on the segment */
#define VM_UFFD_MISSING 0x00000200 /* missing pages tracking */
#define VM_PFNMAP 0x00000400 /* Page-ranges managed without "struct page", just pure PFN */
-#define VM_DENYWRITE 0x00000800 /* ETXTBSY on write attempts.. */
#define VM_UFFD_WP 0x00001000 /* wrprotect pages tracking */
#define VM_LOCKED 0x00002000
diff --git a/include/linux/mman.h b/include/linux/mman.h
index ebb09a964272..bd9aadda047b 100644
--- a/include/linux/mman.h
+++ b/include/linux/mman.h
@@ -153,7 +153,6 @@ static inline unsigned long
calc_vm_flag_bits(unsigned long flags)
{
return _calc_vm_trans(flags, MAP_GROWSDOWN, VM_GROWSDOWN ) |
- _calc_vm_trans(flags, MAP_DENYWRITE, VM_DENYWRITE ) |
_calc_vm_trans(flags, MAP_LOCKED, VM_LOCKED ) |
_calc_vm_trans(flags, MAP_SYNC, VM_SYNC ) |
arch_calc_vm_flag_bits(flags);
diff --git a/include/trace/events/mmflags.h b/include/trace/events/mmflags.h
index 67018d367b9f..e1721ce6381d 100644
--- a/include/trace/events/mmflags.h
+++ b/include/trace/events/mmflags.h
@@ -149,7 +149,6 @@ IF_HAVE_PG_ARCH_2(PG_arch_2, "arch_2" )
{VM_GROWSDOWN, "growsdown" }, \
{VM_UFFD_MISSING, "uffd_missing" }, \
{VM_PFNMAP, "pfnmap" }, \
- {VM_DENYWRITE, "denywrite" }, \
{VM_UFFD_WP, "uffd_wp" }, \
{VM_LOCKED, "locked" }, \
{VM_IO, "io" }, \
diff --git a/kernel/events/core.c b/kernel/events/core.c
index 3dfd463f1831..1ed3eb7aa4c9 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -8184,8 +8184,6 @@ static void perf_event_mmap_event(struct perf_mmap_event *mmap_event)
else
flags = MAP_PRIVATE;
- if (vma->vm_flags & VM_DENYWRITE)
- flags |= MAP_DENYWRITE;
if (vma->vm_flags & VM_LOCKED)
flags |= MAP_LOCKED;
if (is_vm_hugetlb_page(vma))
diff --git a/kernel/fork.c b/kernel/fork.c
index 0681f2973667..fda43ba05d91 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -556,12 +556,9 @@ static __latent_entropy int dup_mmap(struct mm_struct *mm,
tmp->vm_flags &= ~(VM_LOCKED | VM_LOCKONFAULT);
file = tmp->vm_file;
if (file) {
- struct inode *inode = file_inode(file);
struct address_space *mapping = file->f_mapping;
get_file(file);
- if (tmp->vm_flags & VM_DENYWRITE)
- put_write_access(inode);
i_mmap_lock_write(mapping);
if (tmp->vm_flags & VM_SHARED)
mapping_allow_writable(mapping);
diff --git a/lib/test_printf.c b/lib/test_printf.c
index 95a2f82427c7..54f0583dc45d 100644
--- a/lib/test_printf.c
+++ b/lib/test_printf.c
@@ -596,9 +596,8 @@ flags(void)
test("uptodate|dirty|lru|active|swapbacked", "%pGp", &flags);
- flags = VM_READ | VM_EXEC | VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC
- | VM_DENYWRITE;
- test("read|exec|mayread|maywrite|mayexec|denywrite", "%pGv", &flags);
+ flags = VM_READ | VM_EXEC | VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC;
+ test("read|exec|mayread|maywrite|mayexec", "%pGv", &flags);
gfp = GFP_TRANSHUGE;
test("GFP_TRANSHUGE", "%pGg", &gfp);
diff --git a/mm/mmap.c b/mm/mmap.c
index 882f8ee4af1f..b335f8907568 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -142,8 +142,6 @@ void vma_set_page_prot(struct vm_area_struct *vma)
static void __remove_shared_vm_struct(struct vm_area_struct *vma,
struct file *file, struct address_space *mapping)
{
- if (vma->vm_flags & VM_DENYWRITE)
- allow_write_access(file);
if (vma->vm_flags & VM_SHARED)
mapping_unmap_writable(mapping);
@@ -660,8 +658,6 @@ static void __vma_link_file(struct vm_area_struct *vma)
if (file) {
struct address_space *mapping = file->f_mapping;
- if (vma->vm_flags & VM_DENYWRITE)
- put_write_access(file_inode(file));
if (vma->vm_flags & VM_SHARED)
mapping_allow_writable(mapping);
@@ -1785,22 +1781,12 @@ unsigned long mmap_region(struct file *file, unsigned long addr,
vma->vm_pgoff = pgoff;
if (file) {
- if (vm_flags & VM_DENYWRITE) {
- error = deny_write_access(file);
- if (error)
- goto free_vma;
- }
if (vm_flags & VM_SHARED) {
error = mapping_map_writable(file->f_mapping);
if (error)
- goto allow_write_and_free_vma;
+ goto free_vma;
}
- /* ->mmap() can change vma->vm_file, but must guarantee that
- * vma_link() below can deny write-access if VM_DENYWRITE is set
- * and map writably if VM_SHARED is set. This usually means the
- * new file must not have been exposed to user-space, yet.
- */
vma->vm_file = get_file(file);
error = call_mmap(file, vma);
if (error)
@@ -1857,13 +1843,9 @@ unsigned long mmap_region(struct file *file, unsigned long addr,
vma_link(mm, vma, prev, rb_link, rb_parent);
/* Once vma denies write, undo our temporary denial count */
- if (file) {
unmap_writable:
- if (vm_flags & VM_SHARED)
- mapping_unmap_writable(file->f_mapping);
- if (vm_flags & VM_DENYWRITE)
- allow_write_access(file);
- }
+ if (file && vm_flags & VM_SHARED)
+ mapping_unmap_writable(file->f_mapping);
file = vma->vm_file;
out:
perf_event_mmap(vma);
@@ -1903,9 +1885,6 @@ unsigned long mmap_region(struct file *file, unsigned long addr,
charged = 0;
if (vm_flags & VM_SHARED)
mapping_unmap_writable(file->f_mapping);
-allow_write_and_free_vma:
- if (vm_flags & VM_DENYWRITE)
- allow_write_access(file);
free_vma:
vm_area_free(vma);
unacct_error:
--
2.30.2
next prev parent reply other threads:[~2021-04-23 13:18 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-23 13:16 [PATCH RFC 0/7] Remove in-tree usage of MAP_DENYWRITE David Hildenbrand
2021-04-23 13:16 ` [PATCH RFC 1/7] binfmt: don't use MAP_DENYWRITE when loading shared libraries via uselib() David Hildenbrand
2021-04-23 13:16 ` [PATCH RFC 2/7] kernel/fork: factor out atomcially replacing the current MM exe_file David Hildenbrand
2021-04-23 13:16 ` [PATCH RFC 3/7] kernel/fork: always deny write access to " David Hildenbrand
2021-04-23 13:16 ` [PATCH RFC 4/7] binfmt: remove in-tree usage of MAP_DENYWRITE David Hildenbrand
2021-04-23 13:16 ` David Hildenbrand [this message]
2021-04-23 13:16 ` [PATCH RFC 6/7] mm: ignore MAP_DENYWRITE in ksys_mmap_pgoff() David Hildenbrand
2021-04-23 13:16 ` [PATCH RFC 7/7] fs: update documentation of get_write_access() and friends David Hildenbrand
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