From: Gregory Herrero <gregory.herrero(a)oracle.com>
Currently, if a section has a relocation to '_mcount' symbol, a new
__mcount_loc entry will be added whatever the relocation type is.
This is problematic when a relocation to '_mcount' is in the middle of a
section and is not a call for ftrace use.
Such relocation could be generated with below code for example:
bool is_mcount(unsigned long addr)
{
return (target == (unsigned long) &_mcount);
}
With this snippet of code, ftrace will try to patch the mcount location
generated by this code on module load and fail with:
Call trace:
ftrace_bug+0xa0/0x28c
ftrace_process_locs+0x2f4/0x430
ftrace_module_init+0x30/0x38
load_module+0x14f0/0x1e78
__do_sys_finit_module+0x100/0x11c
__arm64_sys_finit_module+0x28/0x34
el0_svc_common+0x88/0x194
el0_svc_handler+0x38/0x8c
el0_svc+0x8/0xc
---[ end trace d828d06b36ad9d59 ]---
ftrace failed to modify
[<ffffa2dbf3a3a41c>] 0xffffa2dbf3a3a41c
actual: 66:a9:3c:90
Initializing ftrace call sites
ftrace record flags: 2000000
(0)
expected tramp: ffffa2dc6cf66724
So Limit the relocation type to R_AARCH64_CALL26 as in perl version of
recordmcount.
Fixes: ed60453fa8f8 ("ARM: 6511/1: ftrace: add ARM support for C version of recordmcount")
Signed-off-by: Gregory Herrero <gregory.herrero(a)oracle.com>
---
scripts/recordmcount.c | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/scripts/recordmcount.c b/scripts/recordmcount.c
index 7225107a9aaf..e59022b3f125 100644
--- a/scripts/recordmcount.c
+++ b/scripts/recordmcount.c
@@ -434,6 +434,11 @@ static int arm_is_fake_mcount(Elf32_Rel const *rp)
return 1;
}
+static int arm64_is_fake_mcount(Elf64_Rel const *rp)
+{
+ return ELF64_R_TYPE(w(rp->r_info)) != R_AARCH64_CALL26;
+}
+
/* 64-bit EM_MIPS has weird ELF64_Rela.r_info.
* http://techpubs.sgi.com/library/manuals/4000/007-4658-001/pdf/007-4658-001.…
* We interpret Table 29 Relocation Operation (Elf64_Rel, Elf64_Rela) [p.40]
@@ -547,6 +552,7 @@ static int do_file(char const *const fname)
make_nop = make_nop_arm64;
rel_type_nop = R_AARCH64_NONE;
ideal_nop = ideal_nop4_arm64;
+ is_fake_mcount64 = arm64_is_fake_mcount;
break;
case EM_IA_64: reltype = R_IA64_IMM64; break;
case EM_MIPS: /* reltype: e_class */ break;
--
2.27.0
If a stage-2 page-table contains an executable, read-only mapping at the
pte level (e.g. due to dirty logging being enabled), a subsequent write
fault to the same page which tries to install a larger block mapping
(e.g. due to dirty logging having been disabled) will erroneously inherit
the exec permission and consequently skip I-cache invalidation for the
rest of the block.
Ensure that exec permission is only inherited by write faults when the
new mapping is of the same size as the existing one. A subsequent
instruction abort will result in I-cache invalidation for the entire
block mapping.
Cc: Marc Zyngier <maz(a)kernel.org>
Cc: Quentin Perret <qperret(a)google.com>
Cc: <stable(a)vger.kernel.org>
Signed-off-by: Will Deacon <will(a)kernel.org>
---
Found by code inspection, rather than something actually going wrong.
arch/arm64/kvm/mmu.c | 9 +++++----
1 file changed, 5 insertions(+), 4 deletions(-)
diff --git a/arch/arm64/kvm/mmu.c b/arch/arm64/kvm/mmu.c
index 8c0035cab6b6..69dc36d1d486 100644
--- a/arch/arm64/kvm/mmu.c
+++ b/arch/arm64/kvm/mmu.c
@@ -1326,7 +1326,7 @@ static bool stage2_get_leaf_entry(struct kvm *kvm, phys_addr_t addr,
return true;
}
-static bool stage2_is_exec(struct kvm *kvm, phys_addr_t addr)
+static bool stage2_is_exec(struct kvm *kvm, phys_addr_t addr, unsigned long sz)
{
pud_t *pudp;
pmd_t *pmdp;
@@ -1338,9 +1338,9 @@ static bool stage2_is_exec(struct kvm *kvm, phys_addr_t addr)
return false;
if (pudp)
- return kvm_s2pud_exec(pudp);
+ return sz == PUD_SIZE && kvm_s2pud_exec(pudp);
else if (pmdp)
- return kvm_s2pmd_exec(pmdp);
+ return sz == PMD_SIZE && kvm_s2pmd_exec(pmdp);
else
return kvm_s2pte_exec(ptep);
}
@@ -1958,7 +1958,8 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa,
* execute permissions, and we preserve whatever we have.
*/
needs_exec = exec_fault ||
- (fault_status == FSC_PERM && stage2_is_exec(kvm, fault_ipa));
+ (fault_status == FSC_PERM &&
+ stage2_is_exec(kvm, fault_ipa, vma_pagesize));
if (vma_pagesize == PUD_SIZE) {
pud_t new_pud = kvm_pfn_pud(pfn, mem_type);
--
2.28.0.rc0.105.gf9edc3c819-goog
target_unpopulated is incremented with nr_pages at the start of the
function, but the call to free_xenballooned_pages will only subtract
pgno number of pages, and thus the rest need to be subtracted before
returning or else accounting will be skewed.
Signed-off-by: Roger Pau Monné <roger.pau(a)citrix.com>
Cc: stable(a)vger.kernel.org
---
Cc: Boris Ostrovsky <boris.ostrovsky(a)oracle.com>
Cc: Juergen Gross <jgross(a)suse.com>
Cc: Stefano Stabellini <sstabellini(a)kernel.org>
Cc: xen-devel(a)lists.xenproject.org
---
drivers/xen/balloon.c | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/drivers/xen/balloon.c b/drivers/xen/balloon.c
index 77c57568e5d7..3cb10ed32557 100644
--- a/drivers/xen/balloon.c
+++ b/drivers/xen/balloon.c
@@ -630,6 +630,12 @@ int alloc_xenballooned_pages(int nr_pages, struct page **pages)
out_undo:
mutex_unlock(&balloon_mutex);
free_xenballooned_pages(pgno, pages);
+ /*
+ * NB: free_xenballooned_pages will only subtract pgno pages, but since
+ * target_unpopulated is incremented with nr_pages at the start we need
+ * to remove the remaining ones also, or accounting will be screwed.
+ */
+ balloon_stats.target_unpopulated -= nr_pages - pgno;
return ret;
}
EXPORT_SYMBOL(alloc_xenballooned_pages);
--
2.27.0
From: Tom Rix <trix(a)redhat.com>
clang static analysis flags this error
qat_uclo.c:297:3: warning: Attempt to free released memory
[unix.Malloc]
kfree(*init_tab_base);
^~~~~~~~~~~~~~~~~~~~~
When input *init_tab_base is null, the function allocates memory for
the head of the list. When there is problem allocating other list
elements the list is unwound and freed. Then a check is made if the
list head was allocated and is also freed.
Keeping track of the what may need to be freed is the variable 'tail_old'.
The unwinding/freeing block is
while (tail_old) {
mem_init = tail_old->next;
kfree(tail_old);
tail_old = mem_init;
}
The problem is that the first element of tail_old is also what was
allocated for the list head
init_header = kzalloc(sizeof(*init_header), GFP_KERNEL);
...
*init_tab_base = init_header;
flag = 1;
}
tail_old = init_header;
So *init_tab_base/init_header are freed twice.
There is another problem.
When the input *init_tab_base is non null the tail_old is calculated by
traveling down the list to first non null entry.
tail_old = init_header;
while (tail_old->next)
tail_old = tail_old->next;
When the unwinding free happens, the last entry of the input list will
be freed.
So the freeing needs a general changed.
If locally allocated the first element of tail_old is freed, else it
is skipped. As a bit of cleanup, reset *init_tab_base if it came in
as null.
Fixes: b4b7e67c917f ("crypto: qat - Intel(R) QAT ucode part of fw loader")
Signed-off-by: Tom Rix <trix(a)redhat.com>
---
drivers/crypto/qat/qat_common/qat_uclo.c | 9 +++++++--
1 file changed, 7 insertions(+), 2 deletions(-)
diff --git a/drivers/crypto/qat/qat_common/qat_uclo.c b/drivers/crypto/qat/qat_common/qat_uclo.c
index 4cc1f436b075..bff759e2f811 100644
--- a/drivers/crypto/qat/qat_common/qat_uclo.c
+++ b/drivers/crypto/qat/qat_common/qat_uclo.c
@@ -288,13 +288,18 @@ static int qat_uclo_create_batch_init_list(struct icp_qat_fw_loader_handle
}
return 0;
out_err:
+ /* Do not free the list head unless we allocated it. */
+ tail_old = tail_old->next;
+ if (flag) {
+ kfree(*init_tab_base);
+ *init_tab_base = NULL;
+ }
+
while (tail_old) {
mem_init = tail_old->next;
kfree(tail_old);
tail_old = mem_init;
}
- if (flag)
- kfree(*init_tab_base);
return -ENOMEM;
}
--
2.18.1
This is a note to let you know that I've just added the patch titled
/dev/mem: Add missing memory barriers for devmem_inode
to my char-misc git tree which can be found at
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc.git
in the char-misc-linus branch.
The patch will show up in the next release of the linux-next tree
(usually sometime within the next 24 hours during the week.)
The patch will hopefully also be merged in Linus's tree for the
next -rc kernel release.
If you have any questions about this process, please let me know.
>From b34e7e298d7a5ed76b3aa327c240c29f1ef6dd22 Mon Sep 17 00:00:00 2001
From: Eric Biggers <ebiggers(a)google.com>
Date: Wed, 15 Jul 2020 23:05:53 -0700
Subject: /dev/mem: Add missing memory barriers for devmem_inode
WRITE_ONCE() isn't the correct way to publish a pointer to a data
structure, since it doesn't include a write memory barrier. Therefore
other tasks may see that the pointer has been set but not see that the
pointed-to memory has finished being initialized yet. Instead a
primitive with "release" semantics is needed.
Use smp_store_release() for this.
The use of READ_ONCE() on the read side is still potentially correct if
there's no control dependency, i.e. if all memory being "published" is
transitively reachable via the pointer itself. But this pairing is
somewhat confusing and error-prone. So just upgrade the read side to
smp_load_acquire() so that it clearly pairs with smp_store_release().
Cc: Arnd Bergmann <arnd(a)arndb.de>
Cc: Ingo Molnar <mingo(a)redhat.com>
Cc: Kees Cook <keescook(a)chromium.org>
Cc: Matthew Wilcox <willy(a)infradead.org>
Cc: Russell King <linux(a)arm.linux.org.uk>
Cc: Andrew Morton <akpm(a)linux-foundation.org>
Fixes: 3234ac664a87 ("/dev/mem: Revoke mappings when a driver claims the region")
Signed-off-by: Eric Biggers <ebiggers(a)google.com>
Cc: stable <stable(a)vger.kernel.org>
Acked-by: Dan Williams <dan.j.williams(a)intel.com>
Link: https://lore.kernel.org/r/20200716060553.24618-1-ebiggers@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org>
---
drivers/char/mem.c | 10 +++++++---
1 file changed, 7 insertions(+), 3 deletions(-)
diff --git a/drivers/char/mem.c b/drivers/char/mem.c
index 934c92dcb9ab..687d4af6945d 100644
--- a/drivers/char/mem.c
+++ b/drivers/char/mem.c
@@ -814,7 +814,8 @@ static struct inode *devmem_inode;
#ifdef CONFIG_IO_STRICT_DEVMEM
void revoke_devmem(struct resource *res)
{
- struct inode *inode = READ_ONCE(devmem_inode);
+ /* pairs with smp_store_release() in devmem_init_inode() */
+ struct inode *inode = smp_load_acquire(&devmem_inode);
/*
* Check that the initialization has completed. Losing the race
@@ -1028,8 +1029,11 @@ static int devmem_init_inode(void)
return rc;
}
- /* publish /dev/mem initialized */
- WRITE_ONCE(devmem_inode, inode);
+ /*
+ * Publish /dev/mem initialized.
+ * Pairs with smp_load_acquire() in revoke_devmem().
+ */
+ smp_store_release(&devmem_inode, inode);
return 0;
}
--
2.27.0
This is a note to let you know that I've just added the patch titled
binder: Don't use mmput() from shrinker function.
to my char-misc git tree which can be found at
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc.git
in the char-misc-linus branch.
The patch will show up in the next release of the linux-next tree
(usually sometime within the next 24 hours during the week.)
The patch will hopefully also be merged in Linus's tree for the
next -rc kernel release.
If you have any questions about this process, please let me know.
>From f867c771f98891841c217fa8459244ed0dd28921 Mon Sep 17 00:00:00 2001
From: Tetsuo Handa <penguin-kernel(a)i-love.sakura.ne.jp>
Date: Fri, 17 Jul 2020 00:12:15 +0900
Subject: binder: Don't use mmput() from shrinker function.
syzbot is reporting that mmput() from shrinker function has a risk of
deadlock [1], for delayed_uprobe_add() from update_ref_ctr() calls
kzalloc(GFP_KERNEL) with delayed_uprobe_lock held, and
uprobe_clear_state() from __mmput() also holds delayed_uprobe_lock.
Commit a1b2289cef92ef0e ("android: binder: drop lru lock in isolate
callback") replaced mmput() with mmput_async() in order to avoid sleeping
with spinlock held. But this patch replaces mmput() with mmput_async() in
order not to start __mmput() from shrinker context.
[1] https://syzkaller.appspot.com/bug?id=bc9e7303f537c41b2b0cc2dfcea3fc42964c2d…
Reported-by: syzbot <syzbot+1068f09c44d151250c33(a)syzkaller.appspotmail.com>
Reported-by: syzbot <syzbot+e5344baa319c9a96edec(a)syzkaller.appspotmail.com>
Signed-off-by: Tetsuo Handa <penguin-kernel(a)I-love.SAKURA.ne.jp>
Reviewed-by: Michal Hocko <mhocko(a)suse.com>
Acked-by: Todd Kjos <tkjos(a)google.com>
Acked-by: Christian Brauner <christian.brauner(a)ubuntu.com>
Cc: stable <stable(a)vger.kernel.org>
Link: https://lore.kernel.org/r/4ba9adb2-43f5-2de0-22de-f6075c1fab50@i-love.sakur…
Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org>
---
drivers/android/binder_alloc.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/android/binder_alloc.c b/drivers/android/binder_alloc.c
index 42c672f1584e..cbe6aa77d50d 100644
--- a/drivers/android/binder_alloc.c
+++ b/drivers/android/binder_alloc.c
@@ -947,7 +947,7 @@ enum lru_status binder_alloc_free_page(struct list_head *item,
trace_binder_unmap_user_end(alloc, index);
}
mmap_read_unlock(mm);
- mmput(mm);
+ mmput_async(mm);
trace_binder_unmap_kernel_start(alloc, index);
--
2.27.0