From: Konstantin Komarov <almaz.alexandrovich(a)paragon-software.com>
[ Upstream commit 22457c047ed971f2f2e33be593ddfabd9639a409 ]
Unfortunately reparse attribute is used for many purposes (several dozens).
It is not possible here to know is this name symlink or not.
To get exactly the type of name we should to open inode (read mft).
getattr for opened file (fstat) correctly returns symlink.
Signed-off-by: Konstantin Komarov <almaz.alexandrovich(a)paragon-software.com>
Signed-off-by: Sasha Levin <sashal(a)kernel.org>
---
fs/ntfs3/dir.c | 30 +++++++++++++++++++++++++-----
1 file changed, 25 insertions(+), 5 deletions(-)
diff --git a/fs/ntfs3/dir.c b/fs/ntfs3/dir.c
index d4d9f4ffb6d9..c2fb76bb28f4 100644
--- a/fs/ntfs3/dir.c
+++ b/fs/ntfs3/dir.c
@@ -309,11 +309,31 @@ static inline int ntfs_filldir(struct ntfs_sb_info *sbi, struct ntfs_inode *ni,
return 0;
}
- /* NTFS: symlinks are "dir + reparse" or "file + reparse" */
- if (fname->dup.fa & FILE_ATTRIBUTE_REPARSE_POINT)
- dt_type = DT_LNK;
- else
- dt_type = (fname->dup.fa & FILE_ATTRIBUTE_DIRECTORY) ? DT_DIR : DT_REG;
+ /*
+ * NTFS: symlinks are "dir + reparse" or "file + reparse"
+ * Unfortunately reparse attribute is used for many purposes (several dozens).
+ * It is not possible here to know is this name symlink or not.
+ * To get exactly the type of name we should to open inode (read mft).
+ * getattr for opened file (fstat) correctly returns symlink.
+ */
+ dt_type = (fname->dup.fa & FILE_ATTRIBUTE_DIRECTORY) ? DT_DIR : DT_REG;
+
+ /*
+ * It is not reliable to detect the type of name using duplicated information
+ * stored in parent directory.
+ * The only correct way to get the type of name - read MFT record and find ATTR_STD.
+ * The code below is not good idea.
+ * It does additional locks/reads just to get the type of name.
+ * Should we use additional mount option to enable branch below?
+ */
+ if ((fname->dup.fa & FILE_ATTRIBUTE_REPARSE_POINT) &&
+ ino != ni->mi.rno) {
+ struct inode *inode = ntfs_iget5(sbi->sb, &e->ref, NULL);
+ if (!IS_ERR_OR_NULL(inode)) {
+ dt_type = fs_umode_to_dtype(inode->i_mode);
+ iput(inode);
+ }
+ }
return !dir_emit(ctx, (s8 *)name, name_len, ino, dt_type);
}
--
2.43.0
From: "Steven Rostedt (Google)" <rostedt(a)goodmis.org>
While looking at improving the saved_cmdlines cache I found a huge amount
of wasted memory that should be used for the cmdlines.
The tracing data saves pids during the trace. At sched switch, if a trace
occurred, it will save the comm of the task that did the trace. This is
saved in a "cache" that maps pids to comms and exposed to user space via
the /sys/kernel/tracing/saved_cmdlines file. Currently it only caches by
default 128 comms.
The structure that uses this creates an array to store the pids using
PID_MAX_DEFAULT (which is usually set to 32768). This causes the structure
to be of the size of 131104 bytes on 64 bit machines.
In hex: 131104 = 0x20020, and since the kernel allocates generic memory in
powers of two, the kernel would allocate 0x40000 or 262144 bytes to store
this structure. That leaves 131040 bytes of wasted space.
Worse, the structure points to an allocated array to store the comm names,
which is 16 bytes times the amount of names to save (currently 128), which
is 2048 bytes. Instead of allocating a separate array, make the structure
end with a variable length string and use the extra space for that.
This is similar to a recommendation that Linus had made about eventfs_inode names:
https://lore.kernel.org/all/20240130190355.11486-5-torvalds@linux-foundatio…
Instead of allocating a separate string array to hold the saved comms,
have the structure end with: char saved_cmdlines[]; and round up to the
next power of two over sizeof(struct saved_cmdline_buffers) + num_cmdlines * TASK_COMM_LEN
It will use this extra space for the saved_cmdline portion.
Now, instead of saving only 128 comms by default, by using this wasted
space at the end of the structure it can save over 8000 comms and even
saves space by removing the need for allocating the other array.
Cc: stable(a)vger.kernel.org
Fixes: 939c7a4f04fcd ("tracing: Introduce saved_cmdlines_size file")
Signed-off-by: Steven Rostedt (Google) <rostedt(a)goodmis.org>
---
kernel/trace/trace.c | 73 +++++++++++++++++++++-----------------------
1 file changed, 34 insertions(+), 39 deletions(-)
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 2a7c6fd934e9..0b3e60b827f7 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -2320,7 +2320,7 @@ struct saved_cmdlines_buffer {
unsigned *map_cmdline_to_pid;
unsigned cmdline_num;
int cmdline_idx;
- char *saved_cmdlines;
+ char saved_cmdlines[];
};
static struct saved_cmdlines_buffer *savedcmd;
@@ -2334,47 +2334,54 @@ static inline void set_cmdline(int idx, const char *cmdline)
strncpy(get_saved_cmdlines(idx), cmdline, TASK_COMM_LEN);
}
-static int allocate_cmdlines_buffer(unsigned int val,
- struct saved_cmdlines_buffer *s)
+static void free_saved_cmdlines_buffer(struct saved_cmdlines_buffer *s)
+{
+ int order = get_order(sizeof(*s) + s->cmdline_num * TASK_COMM_LEN);
+
+ kfree(s->map_cmdline_to_pid);
+ free_pages((unsigned long)s, order);
+}
+
+static struct saved_cmdlines_buffer *allocate_cmdlines_buffer(unsigned int val)
{
+ struct saved_cmdlines_buffer *s;
+ struct page *page;
+ int orig_size, size;
+ int order;
+
+ /* Figure out how much is needed to hold the given number of cmdlines */
+ orig_size = sizeof(*s) + val * TASK_COMM_LEN;
+ order = get_order(orig_size);
+ size = 1 << (order + PAGE_SHIFT);
+ page = alloc_pages(GFP_KERNEL, order);
+ if (!page)
+ return NULL;
+
+ s = page_address(page);
+ memset(s, 0, sizeof(*s));
+
+ /* Round up to actual allocation */
+ val = (size - sizeof(*s)) / TASK_COMM_LEN;
+ s->cmdline_num = val;
+
s->map_cmdline_to_pid = kmalloc_array(val,
sizeof(*s->map_cmdline_to_pid),
GFP_KERNEL);
- if (!s->map_cmdline_to_pid)
- return -ENOMEM;
-
- s->saved_cmdlines = kmalloc_array(TASK_COMM_LEN, val, GFP_KERNEL);
- if (!s->saved_cmdlines) {
- kfree(s->map_cmdline_to_pid);
- return -ENOMEM;
- }
s->cmdline_idx = 0;
- s->cmdline_num = val;
memset(&s->map_pid_to_cmdline, NO_CMDLINE_MAP,
sizeof(s->map_pid_to_cmdline));
memset(s->map_cmdline_to_pid, NO_CMDLINE_MAP,
val * sizeof(*s->map_cmdline_to_pid));
- return 0;
+ return s;
}
static int trace_create_savedcmd(void)
{
- int ret;
-
- savedcmd = kmalloc(sizeof(*savedcmd), GFP_KERNEL);
- if (!savedcmd)
- return -ENOMEM;
-
- ret = allocate_cmdlines_buffer(SAVED_CMDLINES_DEFAULT, savedcmd);
- if (ret < 0) {
- kfree(savedcmd);
- savedcmd = NULL;
- return -ENOMEM;
- }
+ savedcmd = allocate_cmdlines_buffer(SAVED_CMDLINES_DEFAULT);
- return 0;
+ return savedcmd ? 0 : -ENOMEM;
}
int is_tracing_stopped(void)
@@ -6056,26 +6063,14 @@ tracing_saved_cmdlines_size_read(struct file *filp, char __user *ubuf,
return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
}
-static void free_saved_cmdlines_buffer(struct saved_cmdlines_buffer *s)
-{
- kfree(s->saved_cmdlines);
- kfree(s->map_cmdline_to_pid);
- kfree(s);
-}
-
static int tracing_resize_saved_cmdlines(unsigned int val)
{
struct saved_cmdlines_buffer *s, *savedcmd_temp;
- s = kmalloc(sizeof(*s), GFP_KERNEL);
+ s = allocate_cmdlines_buffer(val);
if (!s)
return -ENOMEM;
- if (allocate_cmdlines_buffer(val, s) < 0) {
- kfree(s);
- return -ENOMEM;
- }
-
preempt_disable();
arch_spin_lock(&trace_cmdline_lock);
savedcmd_temp = savedcmd;
--
2.43.0
The quilt patch titled
Subject: fs/proc/task_mmu: add display flag for VM_MAYOVERLAY
has been removed from the -mm tree. Its filename was
fs-proc-task_mmu-add-display-flag-for-vm_mayoverlay.patch
This patch was dropped because it was withdrawn
------------------------------------------------------
From: Anshuman Khandual <anshuman.khandual(a)arm.com>
Subject: fs/proc/task_mmu: add display flag for VM_MAYOVERLAY
Date: Thu, 8 Feb 2024 14:18:05 +0530
VM_UFFD_MISSING flag is mutually exclussive with VM_MAYOVERLAY flag as
they both use the same bit position i.e 0x00000200 in the vm_flags. Let's
update show_smap_vma_flags() to display the correct flags depending on
CONFIG_MMU.
Link: https://lkml.kernel.org/r/20240208084805.1252337-1-anshuman.khandual@arm.com
Fixes: b6b7a8faf05c ("mm/nommu: don't use VM_MAYSHARE for MAP_PRIVATE mappings")
Signed-off-by: Anshuman Khandual <anshuman.khandual(a)arm.com>
Reviewed-by: David Hildenbrand <david(a)redhat.com>
Cc: <stable(a)vger.kernel.org>
Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org>
---
fs/proc/task_mmu.c | 4 ++++
1 file changed, 4 insertions(+)
--- a/fs/proc/task_mmu.c~fs-proc-task_mmu-add-display-flag-for-vm_mayoverlay
+++ a/fs/proc/task_mmu.c
@@ -681,7 +681,11 @@ static void show_smap_vma_flags(struct s
[ilog2(VM_HUGEPAGE)] = "hg",
[ilog2(VM_NOHUGEPAGE)] = "nh",
[ilog2(VM_MERGEABLE)] = "mg",
+#ifdef CONFIG_MMU
[ilog2(VM_UFFD_MISSING)]= "um",
+#else
+ [ilog2(VM_MAYOVERLAY)] = "ov",
+#endif /* CONFIG_MMU */
[ilog2(VM_UFFD_WP)] = "uw",
#ifdef CONFIG_ARM64_MTE
[ilog2(VM_MTE)] = "mt",
_
Patches currently in -mm which might be from anshuman.khandual(a)arm.com are
mm-memblock-add-memblock_rsrv_noinit-into-flagname-array.patch
mm-cma-dont-treat-bad-input-arguments-for-cma_alloc-as-its-failure.patch
mm-cma-drop-config_cma_debug.patch
mm-cma-make-max_cma_areas-=-config_cma_areas.patch
mm-cma-add-sysfs-file-release_pages_success.patch
The following commit has been merged into the x86/urgent branch of tip:
Commit-ID: d794734c9bbfe22f86686dc2909c25f5ffe1a572
Gitweb: https://git.kernel.org/tip/d794734c9bbfe22f86686dc2909c25f5ffe1a572
Author: Steve Wahl <steve.wahl(a)hpe.com>
AuthorDate: Fri, 26 Jan 2024 10:48:41 -06:00
Committer: Dave Hansen <dave.hansen(a)linux.intel.com>
CommitterDate: Mon, 12 Feb 2024 14:53:42 -08:00
x86/mm/ident_map: Use gbpages only where full GB page should be mapped.
When ident_pud_init() uses only gbpages to create identity maps, large
ranges of addresses not actually requested can be included in the
resulting table; a 4K request will map a full GB. On UV systems, this
ends up including regions that will cause hardware to halt the system
if accessed (these are marked "reserved" by BIOS). Even processor
speculation into these regions is enough to trigger the system halt.
Only use gbpages when map creation requests include the full GB page
of space. Fall back to using smaller 2M pages when only portions of a
GB page are included in the request.
No attempt is made to coalesce mapping requests. If a request requires
a map entry at the 2M (pmd) level, subsequent mapping requests within
the same 1G region will also be at the pmd level, even if adjacent or
overlapping such requests could have been combined to map a full
gbpage. Existing usage starts with larger regions and then adds
smaller regions, so this should not have any great consequence.
[ dhansen: fix up comment formatting, simplifty changelog ]
Signed-off-by: Steve Wahl <steve.wahl(a)hpe.com>
Signed-off-by: Dave Hansen <dave.hansen(a)linux.intel.com>
Cc: stable(a)vger.kernel.org
Link: https://lore.kernel.org/all/20240126164841.170866-1-steve.wahl%40hpe.com
---
arch/x86/mm/ident_map.c | 23 ++++++++++++++++++-----
1 file changed, 18 insertions(+), 5 deletions(-)
diff --git a/arch/x86/mm/ident_map.c b/arch/x86/mm/ident_map.c
index 968d700..f50cc21 100644
--- a/arch/x86/mm/ident_map.c
+++ b/arch/x86/mm/ident_map.c
@@ -26,18 +26,31 @@ static int ident_pud_init(struct x86_mapping_info *info, pud_t *pud_page,
for (; addr < end; addr = next) {
pud_t *pud = pud_page + pud_index(addr);
pmd_t *pmd;
+ bool use_gbpage;
next = (addr & PUD_MASK) + PUD_SIZE;
if (next > end)
next = end;
- if (info->direct_gbpages) {
- pud_t pudval;
+ /* if this is already a gbpage, this portion is already mapped */
+ if (pud_large(*pud))
+ continue;
+
+ /* Is using a gbpage allowed? */
+ use_gbpage = info->direct_gbpages;
- if (pud_present(*pud))
- continue;
+ /* Don't use gbpage if it maps more than the requested region. */
+ /* at the begining: */
+ use_gbpage &= ((addr & ~PUD_MASK) == 0);
+ /* ... or at the end: */
+ use_gbpage &= ((next & ~PUD_MASK) == 0);
+
+ /* Never overwrite existing mappings */
+ use_gbpage &= !pud_present(*pud);
+
+ if (use_gbpage) {
+ pud_t pudval;
- addr &= PUD_MASK;
pudval = __pud((addr - info->offset) | info->page_flag);
set_pud(pud, pudval);
continue;
The patch titled
Subject: kasan/test: avoid gcc warning for intentional overflow
has been added to the -mm mm-unstable branch. Its filename is
kasan-test-avoid-gcc-warning-for-intentional-overflow.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patche…
This patch will later appear in the mm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Before you just go and hit "reply", please:
a) Consider who else should be cc'ed
b) Prefer to cc a suitable mailing list as well
c) Ideally: find the original patch on the mailing list and do a
reply-to-all to that, adding suitable additional cc's
*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***
The -mm tree is included into linux-next via the mm-everything
branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
and is updated there every 2-3 working days
------------------------------------------------------
From: Arnd Bergmann <arnd(a)arndb.de>
Subject: kasan/test: avoid gcc warning for intentional overflow
Date: Mon, 12 Feb 2024 12:15:52 +0100
The out-of-bounds test allocates an object that is three bytes too short
in order to validate the bounds checking. Starting with gcc-14, this
causes a compile-time warning as gcc has grown smart enough to understand
the sizeof() logic:
mm/kasan/kasan_test.c: In function 'kmalloc_oob_16':
mm/kasan/kasan_test.c:443:14: error: allocation of insufficient size '13' for type 'struct <anonymous>' with size '16' [-Werror=alloc-size]
443 | ptr1 = kmalloc(sizeof(*ptr1) - 3, GFP_KERNEL);
| ^
Hide the actual computation behind a RELOC_HIDE() that ensures
the compiler misses the intentional bug.
Link: https://lkml.kernel.org/r/20240212111609.869266-1-arnd@kernel.org
Fixes: 3f15801cdc23 ("lib: add kasan test module")
Signed-off-by: Arnd Bergmann <arnd(a)arndb.de>
Cc: Alexander Potapenko <glider(a)google.com>
Cc: Andrey Konovalov <andreyknvl(a)gmail.com>
Cc: Andrey Ryabinin <ryabinin.a.a(a)gmail.com>
Cc: Arnd Bergmann <arnd(a)arndb.de>
Cc: Dmitry Vyukov <dvyukov(a)google.com>
Cc: Marco Elver <elver(a)google.com>
Cc: Vincenzo Frascino <vincenzo.frascino(a)arm.com>
Cc: <stable(a)vger.kernel.org>
Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org>
---
mm/kasan/kasan_test.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
--- a/mm/kasan/kasan_test.c~kasan-test-avoid-gcc-warning-for-intentional-overflow
+++ a/mm/kasan/kasan_test.c
@@ -440,7 +440,8 @@ static void kmalloc_oob_16(struct kunit
/* This test is specifically crafted for the generic mode. */
KASAN_TEST_NEEDS_CONFIG_ON(test, CONFIG_KASAN_GENERIC);
- ptr1 = kmalloc(sizeof(*ptr1) - 3, GFP_KERNEL);
+ /* RELOC_HIDE to prevent gcc from warning about short alloc */
+ ptr1 = RELOC_HIDE(kmalloc(sizeof(*ptr1) - 3, GFP_KERNEL), 0);
KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr1);
ptr2 = kmalloc(sizeof(*ptr2), GFP_KERNEL);
_
Patches currently in -mm which might be from arnd(a)arndb.de are
mm-damon-dbgfs-implement-deprecation-notice-file-fix.patch
kasan-test-avoid-gcc-warning-for-intentional-overflow.patch