linux-stable.git/tools/objtool/check.c, branch v6.1.78

objtool/x86: add missing embedded_insn check

2023-11-02T08:35:33+00:00

When dbf460087755 ("objtool/x86: Fixup frame-pointer vs rethunk")
was backported to some stable branches, the check for dest->embedded_insn
in is_special_call() was missed.  The result is that the warning it
was intended to suppress still appears.  For example on 6.1 (on kernels
before 6.1, the '-s' argument would instead be 'check'):

$ tools/objtool/objtool -s arch/x86/lib/retpoline.o
arch/x86/lib/retpoline.o: warning: objtool: srso_untrain_ret+0xd:
    call without frame pointer save/setup

With this patch, the warning is correctly suppressed, and the
kernel still passes the normal Google kernel developer tests.

Signed-off-by: John Sperbeck 
Signed-off-by: Greg Kroah-Hartman

objtool/x86: Fix SRSO mess

2023-08-27T19:01:31+00:00

commit 4ae68b26c3ab5a82aa271e6e9fc9b1a06e1d6b40 upstream.

Objtool --rethunk does two things:

 - it collects all (tail) call's of __x86_return_thunk and places them
   into .return_sites. These are typically compiler generated, but
   RET also emits this same.

 - it fudges the validation of the __x86_return_thunk symbol; because
   this symbol is inside another instruction, it can't actually find
   the instruction pointed to by the symbol offset and gets upset.

Because these two things pertained to the same symbol, there was no
pressing need to separate these two separate things.

However, alas, along comes SRSO and more crazy things to deal with
appeared.

The SRSO patch itself added the following symbol names to identify as
rethunk:

  'srso_untrain_ret', 'srso_safe_ret' and '__ret'

Where '__ret' is the old retbleed return thunk, 'srso_safe_ret' is a
new similarly embedded return thunk, and 'srso_untrain_ret' is
completely unrelated to anything the above does (and was only included
because of that INT3 vs UD2 issue fixed previous).

Clear things up by adding a second category for the embedded instruction
thing.

Fixes: fb3bd914b3ec ("x86/srso: Add a Speculative RAS Overflow mitigation")
Signed-off-by: Peter Zijlstra (Intel) 
Signed-off-by: Borislav Petkov (AMD) 
Link: https://lore.kernel.org/r/20230814121148.704502245@infradead.org
Signed-off-by: Josh Poimboeuf 
Signed-off-by: Greg Kroah-Hartman

objtool/x86: Fixup frame-pointer vs rethunk

2023-08-26T11:27:00+00:00

commit dbf46008775516f7f25c95b7760041c286299783 upstream.

For stack-validation of a frame-pointer build, objtool validates that
every CALL instruction is preceded by a frame-setup. The new SRSO
return thunks violate this with their RSB stuffing trickery.

Extend the __fentry__ exception to also cover the embedded_insn case
used for this. This cures:

  vmlinux.o: warning: objtool: srso_untrain_ret+0xd: call without frame pointer save/setup

Fixes: 4ae68b26c3ab ("objtool/x86: Fix SRSO mess")
Signed-off-by: Peter Zijlstra (Intel) 
Signed-off-by: Borislav Petkov (AMD) 
Acked-by: Josh Poimboeuf 
Link: https://lore.kernel.org/r/20230816115921.GH980931@hirez.programming.kicks-ass.net
Signed-off-by: Greg Kroah-Hartman

x86/retpoline,kprobes: Fix position of thunk sections with CONFIG_LTO_CLANG

2023-08-26T11:27:00+00:00

commit 79cd2a11224eab86d6673fe8a11d2046ae9d2757 upstream.

The linker script arch/x86/kernel/vmlinux.lds.S matches the thunk
sections ".text.__x86.*" from arch/x86/lib/retpoline.S as follows:

  .text {
    [...]
    TEXT_TEXT
    [...]
    __indirect_thunk_start = .;
    *(.text.__x86.*)
    __indirect_thunk_end = .;
    [...]
  }

Macro TEXT_TEXT references TEXT_MAIN which normally expands to only
".text". However, with CONFIG_LTO_CLANG, TEXT_MAIN becomes
".text .text.[0-9a-zA-Z_]*" which wrongly matches also the thunk
sections. The output layout is then different than expected. For
instance, the currently defined range [__indirect_thunk_start,
__indirect_thunk_end] becomes empty.

Prevent the problem by using ".." as the first separator, for example,
".text..__x86.indirect_thunk". This pattern is utilized by other
explicit section names which start with one of the standard prefixes,
such as ".text" or ".data", and that need to be individually selected in
the linker script.

  [ nathan: Fix conflicts with SRSO and fold in fix issue brought up by
    Andrew Cooper in post-review:
    https://lore.kernel.org/20230803230323.1478869-1-andrew.cooper3@citrix.com ]

Fixes: dc5723b02e52 ("kbuild: add support for Clang LTO")
Signed-off-by: Petr Pavlu 
Signed-off-by: Peter Zijlstra (Intel) 
Signed-off-by: Nathan Chancellor 
Signed-off-by: Borislav Petkov (AMD) 
Link: https://lore.kernel.org/r/20230711091952.27944-2-petr.pavlu@suse.com
Signed-off-by: Greg Kroah-Hartman

x86/cpu: Rename original retbleed methods

2023-08-26T11:26:59+00:00

commit d025b7bac07a6e90b6b98b487f88854ad9247c39 upstream.

Rename the original retbleed return thunk and untrain_ret to
retbleed_return_thunk() and retbleed_untrain_ret().

No functional changes.

Suggested-by: Josh Poimboeuf 
Signed-off-by: Peter Zijlstra (Intel) 
Signed-off-by: Borislav Petkov (AMD) 
Link: https://lore.kernel.org/r/20230814121148.909378169@infradead.org
Signed-off-by: Greg Kroah-Hartman

Revert "objtool: Support addition to set CFA base"

2023-05-11T14:03:32+00:00

[ Upstream commit e18398e80c73e3cc7d9c3d2e0bc06a4af8f4f1cb ]

Commit 468af56a7bba ("objtool: Support addition to set CFA base") was
added as a preparatory patch for arm64 support, but that support never
came.  It triggers a false positive warning on x86, so just revert it
for now.

Fixes the following warning:

  vmlinux.o: warning: objtool: cdce925_regmap_i2c_write+0xdb: stack state mismatch: cfa1=4+120 cfa2=5+40

Fixes: 468af56a7bba ("objtool: Support addition to set CFA base")
Reported-by: kernel test robot 
Signed-off-by: Josh Poimboeuf 
Signed-off-by: Peter Zijlstra (Intel) 
Link: https://lore.kernel.org/oe-kbuild-all/202304080538.j5G6h1AB-lkp@intel.com/
Signed-off-by: Sasha Levin

objtool: Fix memory leak in create_static_call_sections()

2023-03-11T12:55:17+00:00

[ Upstream commit 3da73f102309fe29150e5c35acd20dd82063ff67 ]

strdup() allocates memory for key_name. We need to release the memory in
the following error paths. Add free() to avoid memory leak.

Fixes: 1e7e47883830 ("x86/static_call: Add inline static call implementation for x86-64")
Signed-off-by: Miaoqian Lin 
Signed-off-by: Ingo Molnar 
Link: https://lore.kernel.org/r/20221205080642.558583-1-linmq006@gmail.com
Cc: Josh Poimboeuf 
Cc: Peter Zijlstra 
Signed-off-by: Sasha Levin

objtool: add UACCESS exceptions for __tsan_volatile_read/write

2023-03-10T08:33:28+00:00

[ Upstream commit d5d469247264e56960705dc5ae7e1d014861fe40 ]

A lot of the tsan helpers are already excempt from the UACCESS warnings,
but some more functions were added that need the same thing:

kernel/kcsan/core.o: warning: objtool: __tsan_volatile_read16+0x0: call to __tsan_unaligned_read16() with UACCESS enabled
kernel/kcsan/core.o: warning: objtool: __tsan_volatile_write16+0x0: call to __tsan_unaligned_write16() with UACCESS enabled
vmlinux.o: warning: objtool: __tsan_unaligned_volatile_read16+0x4: call to __tsan_unaligned_read16() with UACCESS enabled
vmlinux.o: warning: objtool: __tsan_unaligned_volatile_write16+0x4: call to __tsan_unaligned_write16() with UACCESS enabled

As Marco points out, these functions don't even call each other
explicitly but instead gcc (but not clang) notices the functions
being identical and turns one symbol into a direct branch to the
other.

Link: https://lkml.kernel.org/r/20230215130058.3836177-4-arnd@kernel.org
Fixes: 75d75b7a4d54 ("kcsan: Support distinguishing volatile accesses")
Signed-off-by: Arnd Bergmann 
Acked-by: Marco Elver 
Cc: Alexander Potapenko 
Cc: Andrey Konovalov 
Cc: Andrey Ryabinin 
Cc: Dmitry Vyukov 
Cc: Josh Poimboeuf 
Cc: Kuan-Ying Lee 
Cc: Peter Zijlstra (Intel) 
Cc: Vincenzo Frascino 
Signed-off-by: Andrew Morton 
Signed-off-by: Sasha Levin

objtool: Fix SEGFAULT

2023-01-04T10:28:57+00:00

[ Upstream commit efb11fdb3e1a9f694fa12b70b21e69e55ec59c36 ]

find_insn() will return NULL in case of failure. Check insn in order
to avoid a kernel Oops for NULL pointer dereference.

Tested-by: Naveen N. Rao 
Reviewed-by: Naveen N. Rao 
Acked-by: Josh Poimboeuf 
Acked-by: Peter Zijlstra (Intel) 
Signed-off-by: Christophe Leroy 
Signed-off-by: Michael Ellerman 
Link: https://lore.kernel.org/r/20221114175754.1131267-9-sv@linux.ibm.com
Signed-off-by: Sasha Levin

objtool, kcsan: Add volatile read/write instrumentation to whitelist

2022-12-31T12:31:48+00:00

[ Upstream commit 63646fcba5bb4b59a19031c21913f94e46a3d0d4 ]

Adds KCSAN's volatile instrumentation to objtool's uaccess whitelist.

Recent kernel change have shown that this was missing from the uaccess
whitelist (since the first upstreamed version of KCSAN):

  mm/gup.o: warning: objtool: fault_in_readable+0x101: call to __tsan_volatile_write1() with UACCESS enabled

Fixes: 75d75b7a4d54 ("kcsan: Support distinguishing volatile accesses")
Signed-off-by: Marco Elver 
Reviewed-by: Dmitry Vyukov 
Signed-off-by: Paul E. McKenney 
Signed-off-by: Sasha Levin