git.kernel.dk Git - linux-2.6-block.git/log

parisc: Always use the self-extracting kernel feature

This patch drops the CONFIG_PARISC_SELF_EXTRACT option.

The palo boot loader is able to decompress a kernel which was compressed
with gzip. That possibility was useful when the Linux kernel
self-extracting feature wasn't implemented yet.

Beside the fact that the self-extracting feature offers much better
compression rates, we do support self-extracting kernels already since
kernel v4.14, so now it's really time to get rid of that old option and
always use the self-extractor.

Signed-off-by: Helge Deller <deller@gmx.de>

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Helge Deller [Thu, 13 Jan 2022 15:35:53 +0000 (16:35 +0100)]

video/fbdev/stifb: Implement the stifb_fillrect() function

The stifb driver (for Artist/HCRX graphics on PA-RISC) was missing
the fillrect function.
Tested on a 715/64 PA-RISC machine and in qemu.

Signed-off-by: Helge Deller <deller@gmx.de>

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Helge Deller [Wed, 8 Dec 2021 10:06:52 +0000 (11:06 +0100)]

parisc: Add vDSO support

Add minimal vDSO support, which provides the signal trampoline helpers,
but none of the userspace syscall helpers like time wrappers.

The big benefit of this vDSO implementation is, that we now don't need
an executeable stack any longer. PA-RISC is one of the last
architectures where an executeable stack was needed in oder to implement
the signal trampolines by putting assembly instructions on the stack
which then gets executed. Instead the kernel will provide the relevant
code in the vDSO page and only put the pointers to the signal
information on the stack.

By dropping the need for executable stacks we avoid running into issues
with applications which want non executable stacks for security reasons.
Additionally, alternative stacks on memory areas without exec
permissions are supported too.

This code is based on an initial implementation by Randolph Chung from 2006:
https://lore.kernel.org/linux-parisc/4544A34A.6080700@tausq.org/

I did the porting and lifted the code to current code base. Dave fixed
the unwind code so that gdb and glibc are able to backtrace through the
code. An additional patch to gdb will be pushed upstream by Dave.

Signed-off-by: Helge Deller <deller@gmx.de>
Signed-off-by: Dave Anglin <dave.anglin@bell.net>
Cc: Randolph Chung <randolph@tausq.org>

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Kumar Kartikeya Dwivedi [Wed, 16 Feb 2022 20:19:43 +0000 (01:49 +0530)]

bpf: Fix crash due to out of bounds access into reg2btf_ids.

When commit e6ac2450d6de ("bpf: Support bpf program calling kernel function") added
kfunc support, it defined reg2btf_ids as a cheap way to translate the verifier
reg type to the appropriate btf_vmlinux BTF ID, however
commit c25b2ae13603 ("bpf: Replace PTR_TO_XXX_OR_NULL with PTR_TO_XXX | PTR_MAYBE_NULL")
moved the __BPF_REG_TYPE_MAX from the last member of bpf_reg_type enum to after
the base register types, and defined other variants using type flag
composition. However, now, the direct usage of reg->type to index into
reg2btf_ids may no longer fall into __BPF_REG_TYPE_MAX range, and hence lead to
out of bounds access and kernel crash on dereference of bad pointer.

Fixes: c25b2ae13603 ("bpf: Replace PTR_TO_XXX_OR_NULL with PTR_TO_XXX | PTR_MAYBE_NULL")
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20220216201943.624869-1-memxor@gmail.com

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Gustavo A. R. Silva [Wed, 16 Feb 2022 20:25:50 +0000 (14:25 -0600)]

Merge branch 'for-next/kspp-fam0' into for-next/kspp

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Gustavo A. R. Silva [Tue, 15 Feb 2022 01:11:44 +0000 (19:11 -0600)]

treewide: Replace zero-length arrays with flexible-array members

There is a regular need in the kernel to provide a way to declare
having a dynamically sized set of trailing elements in a structure.
Kernel code should always use “flexible array members”[1] for these
cases. The older style of one-element or zero-length arrays should
no longer be used[2].

This code was transformed with the help of Coccinelle:
(next-20220214$ spatch --jobs $(getconf _NPROCESSORS_ONLN) --sp-file script.cocci --include-headers --dir . > output.patch)

@@
identifier S, member, array;
type T1, T2;
@@

struct S {
  ...
  T1 member;
  T2 array[
- 0
  ];
};

UAPI and wireless changes were intentionally excluded from this patch
and will be sent out separately.

[1] https://en.wikipedia.org/wiki/Flexible_array_member
[2] https://www.kernel.org/doc/html/v5.16/process/deprecated.html#zero-length-and-one-element-arrays

Link: https://github.com/KSPP/linux/issues/78
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>

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Alexander Lobakin [Sat, 12 Feb 2022 22:21:11 +0000 (22:21 +0000)]

MIPS: smp: fill in sibling and core maps earlier

After enabling CONFIG_SCHED_CORE (landed during 5.14 cycle),
2-core 2-thread-per-core interAptiv (CPS-driven) started emitting
the following:

[    0.025698] CPU1 revision is: 0001a120 (MIPS interAptiv (multi))
[    0.048183] ------------[ cut here ]------------
[    0.048187] WARNING: CPU: 1 PID: 0 at kernel/sched/core.c:6025 sched_core_cpu_starting+0x198/0x240
[    0.048220] Modules linked in:
[    0.048233] CPU: 1 PID: 0 Comm: swapper/1 Not tainted 5.17.0-rc3+ #35 b7b319f24073fd9a3c2aa7ad15fb7993eec0b26f
[    0.048247] Stack : 817f0000 00000004 327804c8 810eb050 00000000 00000004 00000000 c314fdd1
[    0.048278]         830cbd64 819c0000 81800000 817f0000 83070bf4 00000001 830cbd08 00000000
[    0.048307]         00000000 00000000 815fcbc4 00000000 00000000 00000000 00000000 00000000
[    0.048334]         00000000 00000000 00000000 00000000 817f0000 00000000 00000000 817f6f34
[    0.048361]         817f0000 818a3c00 817f0000 00000004 00000000 00000000 4dc33260 0018c933
[    0.048389]         ...
[    0.048396] Call Trace:
[    0.048399] [<8105a7bc>] show_stack+0x3c/0x140
[    0.048424] [<8131c2a0>] dump_stack_lvl+0x60/0x80
[    0.048440] [<8108b5c0>] __warn+0xc0/0xf4
[    0.048454] [<8108b658>] warn_slowpath_fmt+0x64/0x10c
[    0.048467] [<810bd418>] sched_core_cpu_starting+0x198/0x240
[    0.048483] [<810c6514>] sched_cpu_starting+0x14/0x80
[    0.048497] [<8108c0f8>] cpuhp_invoke_callback_range+0x78/0x140
[    0.048510] [<8108d914>] notify_cpu_starting+0x94/0x140
[    0.048523] [<8106593c>] start_secondary+0xbc/0x280
[    0.048539]
[    0.048543] ---[ end trace 0000000000000000 ]---
[    0.048636] Synchronize counters for CPU 1: done.

...for each but CPU 0/boot.
Basic debug printks right before the mentioned line say:

[    0.048170] CPU: 1, smt_mask:

So smt_mask, which is sibling mask obviously, is empty when entering
the function.
This is critical, as sched_core_cpu_starting() calculates
core-scheduling parameters only once per CPU start, and it's crucial
to have all the parameters filled in at that moment (at least it
uses cpu_smt_mask() which in fact is `&cpu_sibling_map[cpu]` on
MIPS).

A bit of debugging led me to that set_cpu_sibling_map() performing
the actual map calculation, was being invocated after
notify_cpu_start(), and exactly the latter function starts CPU HP
callback round (sched_core_cpu_starting() is basically a CPU HP
callback).
While the flow is same on ARM64 (maps after the notifier, although
before calling set_cpu_online()), x86 started calculating sibling
maps earlier than starting the CPU HP callbacks in Linux 4.14 (see
[0] for the reference). Neither me nor my brief tests couldn't find
any potential caveats in calculating the maps right after performing
delay calibration, but the WARN splat is now gone.
The very same debug prints now yield exactly what I expected from
them:

[    0.048433] CPU: 1, smt_mask: 0-1

[0] https://git.kernel.org/pub/scm/linux/kernel/git/mips/linux.git/commit/?id=76ce7cfe35ef

Signed-off-by: Alexander Lobakin <alobakin@pm.me>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>

commit | commitdiff | tree

Chuanhong Guo [Fri, 11 Feb 2022 00:13:44 +0000 (08:13 +0800)]

MIPS: ralink: mt7621: do memory detection on KSEG1

It's reported that current memory detection code occasionally detects
larger memory under some bootloaders.
Current memory detection code tests whether address space wraps around
on KSEG0, which is unreliable because it's cached.

Rewrite memory size detection to perform the same test on KSEG1 instead.
While at it, this patch also does the following two things:
1. use a fixed pattern instead of a random function pointer as the magic
   value.
2. add an additional memory write and a second comparison as part of the
   test to prevent possible smaller memory detection result due to
   leftover values in memory.

Fixes: 139c949f7f0a MIPS: ("ralink: mt7621: add memory detection support")
Reported-by: Rui Salvaterra <rsalvaterra@gmail.com>
Signed-off-by: Chuanhong Guo <gch981213@gmail.com>
Tested-by: Sergio Paracuellos <sergio.paracuellos@gmail.com>
Tested-by: Rui Salvaterra <rsalvaterra@gmail.com>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>

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Linus Torvalds [Tue, 15 Feb 2022 23:28:00 +0000 (15:28 -0800)]

tty: n_tty: do not look ahead for EOL character past the end of the buffer

Daniel Gibson reports that the n_tty code gets line termination wrong in
very specific cases:

"If you feed a line with exactly 64 chars + terminating newline, and
  directly afterwards (without reading) another line into a pseudo
  terminal, the the first read() on the other side will return the 64
  char line *without* terminating newline, and the next read() will
  return the missing terminating newline AND the complete next line (if
  it fits in the buffer)"

and bisected the behavior to commit 3b830a9c34d5 ("tty: convert
tty_ldisc_ops 'read()' function to take a kernel pointer").

Now, digging deeper, it turns out that the behavior isn't exactly new:
what changed in commit 3b830a9c34d5 was that the tty line discipline
.read() function is now passed an intermediate kernel buffer rather than
the final user space buffer.

And that intermediate kernel buffer is 64 bytes in size - thus that
special case with exactly 64 bytes plus terminating newline.

The same problem did exist before, but historically the boundary was not
the 64-byte chunk, but the user-supplied buffer size, which is obviously
generally bigger (and potentially bigger than N_TTY_BUF_SIZE, which
would hide the issue entirely).

The reason is that the n_tty canon_copy_from_read_buf() code would look
ahead for the EOL character one byte further than it would actually
copy.  It would then decide that it had found the terminator, and unmark
it as an EOL character - which in turn explains why the next read
wouldn't then be terminated by it.

Now, the reason it did all this in the first place is related to some
historical and pretty obscure EOF behavior, see commit ac8f3bf8832a
("n_tty: Fix poll() after buffer-limited eof push read") and commit
40d5e0905a03 ("n_tty: Fix EOF push handling").

And the reason for the EOL confusion is that we treat EOF as a special
EOL condition, with the EOL character being NUL (aka "__DISABLED_CHAR"
in the kernel sources).

So that EOF look-ahead also affects the normal EOL handling.

This patch just removes the look-ahead that causes problems, because EOL
is much more critical than the historical "EOF in the middle of a line
that coincides with the end of the buffer" handling ever was.

Now, it is possible that we should indeed re-introduce the "look at next
character to see if it's a EOF" behavior, but if so, that should be done
not at the kernel buffer chunk boundary in canon_copy_from_read_buf(),
but at a higher level, when we run out of the user buffer.

In particular, the place to do that would be at the top of
'n_tty_read()', where we check if it's a continuation of a previously
started read, and there is no more buffer space left, we could decide to
just eat the __DISABLED_CHAR at that point.

But that would be a separate patch, because I suspect nobody actually
cares, and I'd like to get a report about it before bothering.

Fixes: 3b830a9c34d5 ("tty: convert tty_ldisc_ops 'read()' function to take a kernel pointer")
Fixes: ac8f3bf8832a ("n_tty: Fix  poll() after buffer-limited eof push read")
Fixes: 40d5e0905a03 ("n_tty: Fix EOF push handling")
Link: https://bugzilla.kernel.org/show_bug.cgi?id=215611
Reported-and-tested-by: Daniel Gibson <metalcaedes@gmail.com>
Cc: Peter Hurley <peter@hurleysoftware.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jiri Slaby <jirislaby@kernel.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

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