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Clean up the code to not have external function declarations
inside the C source files. Reduces warnings when compiled with W=1.
Signed-off-by: Helge Deller <deller@gmx.de>
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Signed-off-by: Helge Deller <deller@gmx.de>
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Signed-off-by: Helge Deller <deller@gmx.de>
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Signed-off-by: Helge Deller <deller@gmx.de>
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Signed-off-by: Helge Deller <deller@gmx.de>
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Signed-off-by: Helge Deller <deller@gmx.de>
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Signed-off-by: Helge Deller <deller@gmx.de>
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Signed-off-by: Helge Deller <deller@gmx.de>
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Signed-off-by: Helge Deller <deller@gmx.de>
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Signed-off-by: Helge Deller <deller@gmx.de>
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Signed-off-by: Helge Deller <deller@gmx.de>
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Signed-off-by: Helge Deller <deller@gmx.de>
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Signed-off-by: Helge Deller <deller@gmx.de>
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Signed-off-by: Helge Deller <deller@gmx.de>
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Signed-off-by: Helge Deller <deller@gmx.de>
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Signed-off-by: Helge Deller <deller@gmx.de>
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Signed-off-by: Helge Deller <deller@gmx.de>
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Signed-off-by: Helge Deller <deller@gmx.de>
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No need to keep an extra 32-bit audit_classify_syscall() function.
Signed-off-by: Helge Deller <deller@gmx.de>
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Signed-off-by: Helge Deller <deller@gmx.de>
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Fix the STI console to be able to execute either the 64-bit STI ROM code
or the 32-bit STI ROM code.
This is necessary on 64-bit only machines (e.g. C8000 workstation) which
otherwise won't show the STI text console with HP graphic cards like
Visualize-FX5/FX10/FXe.
Note that when calling 32-bit code from a 64-bit kernel one needs to
copy contents on the CPU stack from high memory down below the 4GB
limit.
Tested-by: John David Anglin <dave.anglin@bell.net>
Signed-off-by: Helge Deller <deller@gmx.de>
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Some 64-bit machines require us to call the STI ROM in 64-bit mode, e.g.
with the VisFXe graphic card.
This patch allows drivers to use such 64-bit calling conventions.
Tested-by: John David Anglin <dave.anglin@bell.net>
Signed-off-by: Helge Deller <deller@gmx.de>
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I've now seen a 6-way SMP rp4440 machine, so increase minimum
number of CPUs to 8 for 64-bit kernels.
Signed-off-by: Helge Deller <deller@gmx.de>
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Signed-off-by: Helge Deller <deller@gmx.de>
Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202306122223.HHER4zOo-lkp@intel.com/
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Signed-off-by: Helge Deller <deller@gmx.de>
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A trivial check to check if IRQs are on although they should be off.
Signed-off-by: Helge Deller <deller@gmx.de>
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Move this debug option to the Kconfig.debug file.
Signed-off-by: Helge Deller <deller@gmx.de>
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As already mentioned in my merge message for the 'expand-stack' branch,
we have something like 24 different versions of the page fault path for
all our different architectures, all just _slightly_ different due to
various historical reasons (usually related to exactly when they
branched off the original i386 version, and the details of the other
architectures they had in their history).
And a few of them had some silly mistake in the conversion.
Most of the architectures call the faulting address 'address' in the
fault path. But not all. Some just call it 'addr'. And if you end up
doing a bit too much copy-and-paste, you end up with the wrong version
in the places that do it differently.
In this case it was csky.
Fixes: a050ba1e7422 ("mm/fault: convert remaining simple cases to lock_mm_and_find_vma()")
Reported-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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In commit 8d7071af8907 ("mm: always expand the stack with the mmap write
lock held") I tried to deal with the remaining odd page fault handling
cases. The oddest one is ia64, which has stacks that grow both up and
down. And because ia64 was _so_ odd, I asked people to verify the end
result.
But a close second oddity is parisc, which is the only one that has a
main stack growing up (our "CONFIG_STACK_GROWSUP" config option). But
it looked obvious enough that I didn't worry about it.
I should have worried a bit more. Not because it was particularly
complex, but because I just used the wrong variable name.
The previous vma isn't called "prev", it's called "prev_vma". Blush.
Fixes: 8d7071af8907 ("mm: always expand the stack with the mmap write lock held")
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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The sparc32 conversion to lock_mm_and_find_vma() in commit a050ba1e7422
("mm/fault: convert remaining simple cases to lock_mm_and_find_vma()")
missed the fact that we didn't actually have a 'regs' pointer available
in the 'force_user_fault()' case.
It's there in the regular page fault path ("do_sparc_fault()"), but not
the window underflow/overflow paths.
Which is all fine - we can just pass in a NULL pointer. The register
state is only used to avoid deadlock with kernel faults, which is not
the case for any of these register window faults.
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Fixes: a050ba1e7422 ("mm/fault: convert remaining simple cases to lock_mm_and_find_vma()")
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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The objtool merge in commit 6f612579be9d ("Merge tag 'objtool-core ...")
generated a semantic conflict that was not resolved.
The btrfs_assertfail() entry was removed from the noreturn list in
commit b831306b3b7d ("btrfs: print assertion failure report and stack
trace from the same line") because btrfs_assertfail() was changed from a
noreturn function into a macro.
The noreturn list was then moved from check.c to noreturns.h in commit
6245ce4ab670 ("objtool: Move noreturn function list to separate file"),
and should be removed from that post-merge as well.
Do it explicitly.
Cc: David Sterba <dsterba@suse.com>
Cc: Josh Poimboeuf <jpoimboe@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Since usermodehelper_table() is marked static now, we get a
warning about it being unused when SYSCTL is disabled:
kernel/umh.c:497:12: error: 'proc_cap_handler' defined but not used [-Werror=unused-function]
Just move it inside of the same #ifdef.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Tested-by: Matthieu Baerts <matthieu.baerts@tessares.net>
Fixes: 861dc0b46432 ("sysctl: move umh sysctl registration to its own file")
Acked-by: Randy Dunlap <rdunlap@infradead.org>
Tested-by: Randy Dunlap <rdunlap@infradead.org> # build-tested
[mcgrof: adjust new commit ID for Fixes tag]
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
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In commit a425ac5365f6 ("gup: add warning if some caller would seem to
want stack expansion") I added a temporary warning to catch any strange
GUP users that would be impacted by the fact that GUP no longer extends
the stack.
But it turns out that the warning is most easily triggered through
__access_remote_vm(), that already knows to expand the stack - it just
does it *after* calling GUP. So the warning is easy to trigger by just
running gdb (or similar) and accessing things remotely under the stack.
This just adds a temporary extra "expand stack early" to avoid the
warning for the already converted case - not because the warning is bad,
but because getting the warning for this known good case would then hide
any subsequent warnings for any actually interesting cases.
Let's try to remember to revert this change when we remove the warnings.
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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There is no xas_pause(&xas) in collapse_file()'s main loop, at the points
where it does xas_unlock_irq(&xas) and then continues.
That would explain why, once two weeks ago and twice yesterday, I have
hit the VM_BUG_ON_PAGE(page != xas_load(&xas), page) since "mm/khugepaged:
fix iteration in collapse_file" removed the xas_set(&xas, index) just
before it: xas.xa_node could be left pointing to a stale node, if there
was concurrent activity on the file which transformed its xarray.
I tried inserting xas_pause()s, but then even bootup crashed on that
VM_BUG_ON_PAGE(): there appears to be a subtle "nextness" implicit in
xas_pause().
xas_next() and xas_pause() are good for use in simple loops, but not in
this one: xas_set() worked well until now, so use xas_set(&xas, index)
explicitly at the head of the loop; and change that VM_BUG_ON_PAGE() not
to need its own xas_set(), and not to interfere with the xa_state (which
would probably stop the crashes from xas_pause(), but I trust that less).
The user-visible effects of this bug (if VM_BUG_ONs are configured out)
would be data loss and data leak - potentially - though in practice I
expect it is more likely that a subsequent check (e.g. on mapping or on
nr_none) would notice an inconsistency, and just abandon the collapse.
Link: https://lore.kernel.org/linux-mm/f18e4b64-3f88-a8ab-56cc-d1f5f9c58d4@google.com/
Fixes: c8a8f3b4a95a ("mm/khugepaged: fix iteration in collapse_file")
Signed-off-by: Hugh Dickins <hughd@google.com>
Cc: stable@kernel.org
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: David Stevens <stevensd@chromium.org>
Cc: Peter Xu <peterx@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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This is the new-and-improved attempt at avoiding huge memory load spikes
when the user space boot sequence tries to load hundreds (or even
thousands) of redundant duplicate modules in parallel.
See commit 9828ed3f695a ("module: error out early on concurrent load of
the same module file") for background and an earlier failed attempt that
was reverted.
That earlier attempt just said "concurrently loading the same module is
silly, just open the module file exclusively and return -ETXTBSY if
somebody else is already loading it".
While it is true that concurrent module loads of the same module is
silly, the reason that earlier attempt then failed was that the
concurrently loaded module would often be a prerequisite for another
module.
Thus failing to load the prerequisite would then cause cascading
failures of the other modules, rather than just short-circuiting that
one unnecessary module load.
At the same time, we still really don't want to load the contents of the
same module file hundreds of times, only to then wait for an eventually
successful load, and have everybody else return -EEXIST.
As a result, this takes another approach, and treats concurrent module
loads from the same file as "idempotent" in the inode. So if one module
load is ongoing, we don't start a new one, but instead just wait for the
first one to complete and return the same return value as it did.
So unlike the first attempt, this does not return early: the intent is
not to speed up the boot, but to avoid a thundering herd problem in
allocating memory (both physical and virtual) for a module more than
once.
Also note that this does change behavior: it used to be that when you
had concurrent loads, you'd have one "winner" that would return success,
and everybody else would return -EEXIST.
In contrast, this idempotent logic goes all Oprah on the problem, and
says "You are a winner! And you are a winner! We are ALL winners". But
since there's no possible actual real semantic difference between "you
loaded the module" and "somebody else already loaded the module", this
is more of a feel-good change than an actual honest-to-goodness semantic
change.
Of course, any true Johnny-come-latelies that don't get caught in the
concurrency filter will still return -EEXIST. It's no different from
not even getting a seat at an Oprah taping. That's life.
See the long thread on the kernel mailing list about this all, which
includes some numbers for memory use before and after the patch.
Link: https://lore.kernel.org/lkml/20230524213620.3509138-1-mcgrof@kernel.org/
Reviewed-by: Johan Hovold <johan@kernel.org>
Tested-by: Johan Hovold <johan@kernel.org>
Tested-by: Luis Chamberlain <mcgrof@kernel.org>
Tested-by: Dan Williams <dan.j.williams@intel.com>
Tested-by: Rudi Heitbaum <rudi@heitbaum..com>
Tested-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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This will simplify the next step, where we can then key off the inode to
do one idempotent module load.
Let's do the obvious re-organization in one step, and then the new code
in another.
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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The memory encryption initialization logic was moved from init/main.c
into arch_cpu_finalize_init() in commit 439e17576eb4 ("init, x86: Move
mem_encrypt_init() into arch_cpu_finalize_init()"), but a stale
declaration for the init function was left in <linux/init.h>.
And didn't cause any problems if you had X86_MEM_ENCRYPT enabled, which
apparently everybody involved did have. See also commit 0a9567ac5e6a
("x86/mem_encrypt: Unbreak the AMD_MEM_ENCRYPT=n build") in this whole
sad saga of conflicting declarations for different situations.
Reported-by: Matthew Wilcox <willy@infradead.org>
Fixes: 439e17576eb4 init, x86: Move mem_encrypt_init() into arch_cpu_finalize_init()
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Commit ca5e863233e8 ("mm/gup: remove vmas parameter from
get_user_pages_remote()") removed the vma argument from GUP handling,
and instead added a helper function (get_user_page_vma_remote()) that
looks it up separately using 'vma_lookup()'. And then converted
existing users that needed a vma to use the helper instead.
However, the helper function intentionally acts exactly like the old
get_user_pages_remote() did, and only fills in 'vma' on successful page
lookup. Fine so far.
However, __access_remote_vm() wants the vma even for the unsuccessful
case, and used to do a
vma = vma_lookup(mm, addr);
explicitly to look it up when the get_user_page() failed.
However, that conversion commit incorrectly removed that vma lookup,
thinking that get_user_page_vma_remote() would have done it. Not so.
So add the vma_lookup() back in.
Fixes: ca5e863233e8 ("mm/gup: remove vmas parameter from get_user_pages_remote()")
Cc: Lorenzo Stoakes <lstoakes@gmail.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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When user_events are disabled, it's write operation should return -EBADF.
Add this test cases.
Link: https://lkml.kernel.org/r/20230626111344.19136-4-sunliming@kylinos.cn
Acked-by: Beau Belgrave <beaub@linux.microsoft.com>
Signed-off-by: sunliming <sunliming@kylinos.cn>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
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The user_event has not be enabled in write_fault test in ftrace
self-test, Just enable it.
Link: https://lkml.kernel.org/r/20230626111344.19136-3-sunliming@kylinos.cn
Acked-by: Beau Belgrave <beaub@linux.microsoft.com>
Signed-off-by: sunliming <sunliming@kylinos.cn>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
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The writing operation return the count of writes regardless of whether events
are enabled or disabled. Switch it to return -EBADF to indicates that the event
is disabled.
Link: https://lkml.kernel.org/r/20230626111344.19136-2-sunliming@kylinos.cn
Cc: stable@vger.kernel.org
7f5a08c79df35 ("user_events: Add minimal support for trace_event into ftrace")
Acked-by: Beau Belgrave <beaub@linux.microsoft.com>
Signed-off-by: sunliming <sunliming@kylinos.cn>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
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If mas_store_gfp() in the gather loop failed, the 'error' variable that
ultimately gets returned was not being set. In many cases, its original
value of -ENOMEM was still in place, and that was fine. But if VMAs had
been split at the start or end of the range, then 'error' could be zero.
Change to the 'error = foo(); if (error) goto …' idiom to fix the bug.
Also clean up a later case which avoided the same bug by *explicitly*
setting error = -ENOMEM right before calling the function that might
return -ENOMEM.
In a final cosmetic change, move the 'Point of no return' comment to
*after* the goto. That's been in the wrong place since the preallocation
was removed, and this new error path was added.
Fixes: 606c812eb1d5 ("mm/mmap: Fix error path in do_vmi_align_munmap()")
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Cc: stable@vger.kernel.org
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Liam R. Howlett <Liam.Howlett@oracle.com>
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This reverts commit 6ebe94baa2b9ddf3ccbb7f94df6ab26234532734.
The patch "nios2: Convert __pte_free_tlb() to use ptdescs" was supposed
to go together with a patchset that Vishal Moola had planned taking it
through the mm tree. By just having this patch, all NIOS2 builds are
broken.
Signed-off-by: Dinh Nguyen <dinguyen@kernel.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Recently, our friends from bluetooth subsystem reported [1] that after
commit 5e2ff6704a27 ("scm: add SO_PASSPIDFD and SCM_PIDFD") scm_recv()
helper become unusable in kernel modules (because it uses unexported
pidfd_prepare() API).
We were aware of this issue and workarounded it in a hard way
by commit 97154bcf4d1b ("af_unix: Kconfig: make CONFIG_UNIX bool").
But recently a new functionality was added in the scope of commit
817efd3cad74 ("Bluetooth: hci_sock: Forward credentials to monitor")
and after that bluetooth can't be compiled as a kernel module.
After some discussion in [1] we decided to split scm_recv() into
two helpers, one won't support SCM_PIDFD (used for unix sockets),
and another one will be completely the same as it was before commit
5e2ff6704a27 ("scm: add SO_PASSPIDFD and SCM_PIDFD").
Link: https://lore.kernel.org/lkml/CAJqdLrpFcga4n7wxBhsFqPQiN8PKFVr6U10fKcJ9W7AcZn+o6Q@mail.gmail.com/ [1]
Fixes: 5e2ff6704a27 ("scm: add SO_PASSPIDFD and SCM_PIDFD")
Signed-off-by: Alexander Mikhalitsyn <aleksandr.mikhalitsyn@canonical.com>
Reviewed-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Link: https://lore.kernel.org/r/20230627174314.67688-3-kuniyu@amazon.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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syzkaller hit a WARN_ON_ONCE(!scm->pid) in scm_pidfd_recv().
In unix_stream_read_generic(), if there is no skb in the queue, we could
bail out the do-while loop without calling scm_set_cred():
1. No skb in the queue
2. sk is non-blocking
or
shutdown(sk, RCV_SHUTDOWN) is called concurrently
or
peer calls close()
If the socket is configured with SO_PASSPIDFD, scm_pidfd_recv() would
populate cmsg with garbage emitting the warning.
Let's skip SCM_PIDFD if scm->pid is NULL in scm_pidfd_recv().
Note another way would be skip calling scm_recv() in such cases, but this
caused a regression resulting in commit 9d797ee2dce1 ("Revert "af_unix:
Call scm_recv() only after scm_set_cred()."").
WARNING: CPU: 1 PID: 3245 at include/net/scm.h:138 scm_pidfd_recv include/net/scm.h:138 [inline]
WARNING: CPU: 1 PID: 3245 at include/net/scm.h:138 scm_recv.constprop.0+0x754/0x850 include/net/scm.h:177
Modules linked in:
CPU: 1 PID: 3245 Comm: syz-executor.1 Not tainted 6.4.0-rc5-01219-gfa0e21fa4443 #2
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.0-0-gd239552ce722-prebuilt.qemu.org 04/01/2014
RIP: 0010:scm_pidfd_recv include/net/scm.h:138 [inline]
RIP: 0010:scm_recv.constprop.0+0x754/0x850 include/net/scm.h:177
Code: 67 fd e9 55 fd ff ff e8 4a 70 67 fd e9 7f fd ff ff e8 40 70 67 fd e9 3e fb ff ff e8 36 70 67 fd e9 02 fd ff ff e8 8c 3a 20 fd <0f> 0b e9 fe fb ff ff e8 50 70 67 fd e9 2e f9 ff ff e8 46 70 67 fd
RSP: 0018:ffffc90009af7660 EFLAGS: 00010216
RAX: 00000000000000a1 RBX: ffff888041e58a80 RCX: ffffc90003852000
RDX: 0000000000040000 RSI: ffffffff842675b4 RDI: 0000000000000007
RBP: ffffc90009af7810 R08: 0000000000000007 R09: 0000000000000013
R10: 00000000000000f8 R11: 0000000000000001 R12: ffffc90009af7db0
R13: 0000000000000000 R14: ffff888041e58a88 R15: 1ffff9200135eecc
FS: 00007f6b7113f640(0000) GS:ffff88806cf00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f6b7111de38 CR3: 0000000012a6e002 CR4: 0000000000770ee0
PKRU: 55555554
Call Trace:
<TASK>
unix_stream_read_generic+0x5fe/0x1f50 net/unix/af_unix.c:2830
unix_stream_recvmsg+0x194/0x1c0 net/unix/af_unix.c:2880
sock_recvmsg_nosec net/socket.c:1019 [inline]
sock_recvmsg+0x188/0x1d0 net/socket.c:1040
____sys_recvmsg+0x210/0x610 net/socket.c:2712
___sys_recvmsg+0xff/0x190 net/socket.c:2754
do_recvmmsg+0x25d/0x6c0 net/socket.c:2848
__sys_recvmmsg net/socket.c:2927 [inline]
__do_sys_recvmmsg net/socket.c:2950 [inline]
__se_sys_recvmmsg net/socket.c:2943 [inline]
__x64_sys_recvmmsg+0x224/0x290 net/socket.c:2943
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x3f/0x90 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x72/0xdc
RIP: 0033:0x7f6b71da2e5d
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 90 f3 0f 1e fa 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d 73 9f 1b 00 f7 d8 64 89 01 48
RSP: 002b:00007f6b7113ecc8 EFLAGS: 00000246 ORIG_RAX: 000000000000012b
RAX: ffffffffffffffda RBX: 00000000004bc050 RCX: 00007f6b71da2e5d
RDX: 0000000000000007 RSI: 0000000020006600 RDI: 000000000000000b
RBP: 00000000004bc050 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000120 R11: 0000000000000246 R12: 0000000000000000
R13: 000000000000006e R14: 00007f6b71e03530 R15: 0000000000000000
</TASK>
Fixes: 5e2ff6704a27 ("scm: add SO_PASSPIDFD and SCM_PIDFD")
Reported-by: syzkaller <syzkaller@googlegroups.com>
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Link: https://lore.kernel.org/r/20230627174314.67688-2-kuniyu@amazon.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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The bnxt_re_mmap_entry_insert() function returns NULL, not error pointers.
Update the check for errors accordingly.
Fixes: 360da60d6c6e ("RDMA/bnxt_re: Enable low latency push")
Link: https://lore.kernel.org/r/8d92e85f-626b-4eca-8501-ca7024cfc0ee@moroto.mountain
Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
Acked-by: Selvin Xavier <selvin.xavier@broadcom.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
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Simplify comparison, no functional changes.
Cc: Bryan Whitehead <bryan.whitehead@microchip.com>
Cc: UNGLinuxDriver@microchip.com
Suggested-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Moritz Fischer <moritzf@google.com>
Link: https://lore.kernel.org/r/20230627035432.1296760-1-moritzf@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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It feels very unlikely that anybody would want to do a GUP in an
unmapped area under the stack pointer, but real users sometimes do some
really strange things. So add a (temporary) warning for the case where
a GUP fails and expanding the stack might have made it work.
It's trivial to do the expansion in the caller as part of getting the mm
lock in the first place - see __access_remote_vm() for ptrace, for
example - it's just that it's unnecessarily painful to do it deep in the
guts of the GUP lookup when we might have to drop and re-take the lock.
I doubt anybody actually does anything quite this strange, but let's be
proactive: adding these warnings is simple, and will make debugging it
much easier if they trigger.
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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This finishes the job of always holding the mmap write lock when
extending the user stack vma, and removes the 'write_locked' argument
from the vm helper functions again.
For some cases, we just avoid expanding the stack at all: drivers and
page pinning really shouldn't be extending any stacks. Let's see if any
strange users really wanted that.
It's worth noting that architectures that weren't converted to the new
lock_mm_and_find_vma() helper function are left using the legacy
"expand_stack()" function, but it has been changed to drop the mmap_lock
and take it for writing while expanding the vma. This makes it fairly
straightforward to convert the remaining architectures.
As a result of dropping and re-taking the lock, the calling conventions
for this function have also changed, since the old vma may no longer be
valid. So it will now return the new vma if successful, and NULL - and
the lock dropped - if the area could not be extended.
Tested-by: Vegard Nossum <vegard.nossum@oracle.com>
Tested-by: John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de> # ia64
Tested-by: Frank Scheiner <frank.scheiner@web.de> # ia64
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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syzbot reported a warning in __local_bh_enable_ip(). [0]
Commit 8d61f926d420 ("netlink: fix potential deadlock in
netlink_set_err()") converted read_lock(&nl_table_lock) to
read_lock_irqsave() in __netlink_diag_dump() to prevent a deadlock.
However, __netlink_diag_dump() calls sock_i_ino() that uses
read_lock_bh() and read_unlock_bh(). If CONFIG_TRACE_IRQFLAGS=y,
read_unlock_bh() finally enables IRQ even though it should stay
disabled until the following read_unlock_irqrestore().
Using read_lock() in sock_i_ino() would trigger a lockdep splat
in another place that was fixed in commit f064af1e500a ("net: fix
a lockdep splat"), so let's add __sock_i_ino() that would be safe
to use under BH disabled.
[0]:
WARNING: CPU: 0 PID: 5012 at kernel/softirq.c:376 __local_bh_enable_ip+0xbe/0x130 kernel/softirq.c:376
Modules linked in:
CPU: 0 PID: 5012 Comm: syz-executor487 Not tainted 6.4.0-rc7-syzkaller-00202-g6f68fc395f49 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/27/2023
RIP: 0010:__local_bh_enable_ip+0xbe/0x130 kernel/softirq.c:376
Code: 45 bf 01 00 00 00 e8 91 5b 0a 00 e8 3c 15 3d 00 fb 65 8b 05 ec e9 b5 7e 85 c0 74 58 5b 5d c3 65 8b 05 b2 b6 b4 7e 85 c0 75 a2 <0f> 0b eb 9e e8 89 15 3d 00 eb 9f 48 89 ef e8 6f 49 18 00 eb a8 0f
RSP: 0018:ffffc90003a1f3d0 EFLAGS: 00010046
RAX: 0000000000000000 RBX: 0000000000000201 RCX: 1ffffffff1cf5996
RDX: 0000000000000000 RSI: 0000000000000201 RDI: ffffffff8805c6f3
RBP: ffffffff8805c6f3 R08: 0000000000000001 R09: ffff8880152b03a3
R10: ffffed1002a56074 R11: 0000000000000005 R12: 00000000000073e4
R13: dffffc0000000000 R14: 0000000000000002 R15: 0000000000000000
FS: 0000555556726300(0000) GS:ffff8880b9800000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000000045ad50 CR3: 000000007c646000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
sock_i_ino+0x83/0xa0 net/core/sock.c:2559
__netlink_diag_dump+0x45c/0x790 net/netlink/diag.c:171
netlink_diag_dump+0xd6/0x230 net/netlink/diag.c:207
netlink_dump+0x570/0xc50 net/netlink/af_netlink.c:2269
__netlink_dump_start+0x64b/0x910 net/netlink/af_netlink.c:2374
netlink_dump_start include/linux/netlink.h:329 [inline]
netlink_diag_handler_dump+0x1ae/0x250 net/netlink/diag.c:238
__sock_diag_cmd net/core/sock_diag.c:238 [inline]
sock_diag_rcv_msg+0x31e/0x440 net/core/sock_diag.c:269
netlink_rcv_skb+0x165/0x440 net/netlink/af_netlink.c:2547
sock_diag_rcv+0x2a/0x40 net/core/sock_diag.c:280
netlink_unicast_kernel net/netlink/af_netlink.c:1339 [inline]
netlink_unicast+0x547/0x7f0 net/netlink/af_netlink.c:1365
netlink_sendmsg+0x925/0xe30 net/netlink/af_netlink.c:1914
sock_sendmsg_nosec net/socket.c:724 [inline]
sock_sendmsg+0xde/0x190 net/socket.c:747
____sys_sendmsg+0x71c/0x900 net/socket.c:2503
___sys_sendmsg+0x110/0x1b0 net/socket.c:2557
__sys_sendmsg+0xf7/0x1c0 net/socket.c:2586
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7f5303aaabb9
Code: 28 c3 e8 2a 14 00 00 66 2e 0f 1f 84 00 00 00 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 c0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffc7506e548 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f5303aaabb9
RDX: 0000000000000000 RSI: 0000000020000180 RDI: 0000000000000003
RBP: 00007f5303a6ed60 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f5303a6edf0
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
</TASK>
Fixes: 8d61f926d420 ("netlink: fix potential deadlock in netlink_set_err()")
Reported-by: syzbot+5da61cf6a9bc1902d422@syzkaller.appspotmail.com
Link: https://syzkaller.appspot.com/bug?extid=5da61cf6a9bc1902d422
Suggested-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Link: https://lore.kernel.org/r/20230626164313.52528-1-kuniyu@amazon.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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Helge Deller
Linus Torvalds
Ingo Molnar
Arnd Bergmann
Hugh Dickins
sunliming
David Woodhouse
Dinh Nguyen
Alexander Mikhalitsyn
Kuniyuki Iwashima
Dan Carpenter
Moritz Fischer