linux-stable.git/tools, branch v5.4.41

objtool: Fix stack offset tracking for indirect CFAs

2020-05-14T05:58:29+00:00

commit d8dd25a461e4eec7190cb9d66616aceacc5110ad upstream.

When the current frame address (CFA) is stored on the stack (i.e.,
cfa->base == CFI_SP_INDIRECT), objtool neglects to adjust the stack
offset when there are subsequent pushes or pops.  This results in bad
ORC data at the end of the ENTER_IRQ_STACK macro, when it puts the
previous stack pointer on the stack and does a subsequent push.

This fixes the following unwinder warning:

  WARNING: can't dereference registers at 00000000f0a6bdba for ip interrupt_entry+0x9f/0xa0

Fixes: 627fce14809b ("objtool: Add ORC unwind table generation")
Reported-by: Vince Weaver 
Reported-by: Dave Jones 
Reported-by: Steven Rostedt 
Reported-by: Vegard Nossum 
Reported-by: Joe Mario 
Reviewed-by: Miroslav Benes 
Signed-off-by: Josh Poimboeuf 
Signed-off-by: Ingo Molnar 
Cc: Andy Lutomirski 
Cc: Jann Horn 
Cc: Peter Zijlstra 
Cc: Thomas Gleixner 
Link: https://lore.kernel.org/r/853d5d691b29e250333332f09b8e27410b2d9924.1587808742.git.jpoimboe@redhat.com
Signed-off-by: Greg Kroah-Hartman

iocost: protect iocg->abs_vdebt with iocg->waitq.lock

2020-05-14T05:58:27+00:00

commit 0b80f9866e6bbfb905140ed8787ff2af03652c0c upstream.

abs_vdebt is an atomic_64 which tracks how much over budget a given cgroup
is and controls the activation of use_delay mechanism. Once a cgroup goes
over budget from forced IOs, it has to pay it back with its future budget.
The progress guarantee on debt paying comes from the iocg being active -
active iocgs are processed by the periodic timer, which ensures that as time
passes the debts dissipate and the iocg returns to normal operation.

However, both iocg activation and vdebt handling are asynchronous and a
sequence like the following may happen.

1. The iocg is in the process of being deactivated by the periodic timer.

2. A bio enters ioc_rqos_throttle(), calls iocg_activate() which returns
   without anything because it still sees that the iocg is already active.

3. The iocg is deactivated.

4. The bio from #2 is over budget but needs to be forced. It increases
   abs_vdebt and goes over the threshold and enables use_delay.

5. IO control is enabled for the iocg's subtree and now IOs are attributed
   to the descendant cgroups and the iocg itself no longer issues IOs.

This leaves the iocg with stuck abs_vdebt - it has debt but inactive and no
further IOs which can activate it. This can end up unduly punishing all the
descendants cgroups.

The usual throttling path has the same issue - the iocg must be active while
throttled to ensure that future event will wake it up - and solves the
problem by synchronizing the throttling path with a spinlock. abs_vdebt
handling is another form of overage handling and shares a lot of
characteristics including the fact that it isn't in the hottest path.

This patch fixes the above and other possible races by strictly
synchronizing abs_vdebt and use_delay handling with iocg->waitq.lock.

Signed-off-by: Tejun Heo 
Reported-by: Vlad Dmitriev 
Cc: stable@vger.kernel.org # v5.4+
Fixes: e1518f63f246 ("blk-iocost: Don't let merges push vtime into the future")
Signed-off-by: Jens Axboe 
Signed-off-by: Greg Kroah-Hartman

tools headers UAPI: Sync copy of arm64's asm/unistd.h with the kernel sources

2020-05-10T08:31:33+00:00

commit c75bec79fc080039e4575a0f239ea7b111aabe88 upstream.

To get the changes in:

  3e3c8ca5a351 ("arm64: Move __ARCH_WANT_SYS_CLONE3 definition to uapi headers")

Silencing this tools/perf/ build warning:

  Warning: Kernel ABI header at 'tools/arch/arm64/include/uapi/asm/unistd.h' differs from latest version at 'arch/arm64/include/uapi/asm/unistd.h'
  diff -u tools/arch/arm64/include/uapi/asm/unistd.h arch/arm64/include/uapi/asm/unistd.h

Which will probably end up enabling the use of "clone3" in 'perf trace -e',
haven't checked the build with this change on an arm64 system.

Cc: Adrian Hunter 
Cc: Amanieu d'Antras 
Cc: Christian Brauner 
Cc: Jiri Olsa 
Cc: Namhyung Kim 
Signed-off-by: Arnaldo Carvalho de Melo 
Signed-off-by: Greg Kroah-Hartman

libbpf: Fix readelf output parsing for Fedora

2020-05-10T08:31:32+00:00

commit aa915931ac3e53ccf371308e6750da510e3591dd upstream.

Fedora binutils has been patched to show "other info" for a symbol at the
end of the line. This was done in order to support unmaintained scripts
that would break with the extra info. [1]

[1] https://src.fedoraproject.org/rpms/binutils/c/b8265c46f7ddae23a792ee8306fbaaeacba83bf8

This in turn has been done to fix the build of ruby, because of checksec.
[2] Thanks Michael Ellerman for the pointer.

[2] https://bugzilla.redhat.com/show_bug.cgi?id=1479302

As libbpf Makefile is not unmaintained, we can simply deal with either
output format, by just removing the "other info" field, as it always comes
inside brackets.

Fixes: 3464afdf11f9 (libbpf: Fix readelf output parsing on powerpc with recent binutils)
Reported-by: Justin Forbes 
Signed-off-by: Thadeu Lima de Souza Cascardo 
Signed-off-by: Alexei Starovoitov 
Acked-by: Andrii Nakryiko 
Cc: Aurelien Jarno 
Link: https://lore.kernel.org/bpf/20191213101114.GA3986@calabresa
Signed-off-by: Greg Kroah-Hartman

selftests/ipc: Fix test failure seen after initial test run

2020-05-10T08:31:23+00:00

[ Upstream commit b87080eab4c1377706c113fc9c0157f19ea8fed1 ]

After successfully running the IPC msgque test once, subsequent runs
result in a test failure:

  $ sudo ./run_kselftest.sh
  TAP version 13
  1..1
  # selftests: ipc: msgque
  # Failed to get stats for IPC queue with id 0
  # Failed to dump queue: -22
  # Bail out!
  # # Pass 0 Fail 0 Xfail 0 Xpass 0 Skip 0 Error 0
  not ok 1 selftests: ipc: msgque # exit=1

The dump_queue() function loops through the possible message queue index
values using calls to msgctl(kern_id, MSG_STAT, ...) where kern_id
represents the index value. The first time the test is ran, the initial
index value of 0 is valid and the test is able to complete. The index
value of 0 is not valid in subsequent test runs and the loop attempts to
try index values of 1, 2, 3, and so on until a valid index value is
found that corresponds to the message queue created earlier in the test.

The msgctl() syscall returns -1 and sets errno to EINVAL when invalid
index values are used. The test failure is caused by incorrectly
comparing errno to -EINVAL when cycling through possible index values.

Fix invalid test failures on subsequent runs of the msgque test by
correctly comparing errno values to a non-negated EINVAL.

Fixes: 3a665531a3b7 ("selftests: IPC message queue copy feature test")
Signed-off-by: Tyler Hicks 
Signed-off-by: Shuah Khan 
Signed-off-by: Sasha Levin

objtool: Support Clang non-section symbols in ORC dump

2020-05-02T06:48:57+00:00

[ Upstream commit 8782e7cab51b6bf01a5a86471dd82228af1ac185 ]

Historically, the relocation symbols for ORC entries have only been
section symbols:

  .text+0: sp:sp+8 bp:(und) type:call end:0

However, the Clang assembler is aggressive about stripping section
symbols.  In that case we will need to use function symbols:

  freezing_slow_path+0: sp:sp+8 bp:(und) type:call end:0

In preparation for the generation of such entries in "objtool orc
generate", add support for reading them in "objtool orc dump".

Signed-off-by: Josh Poimboeuf 
Signed-off-by: Borislav Petkov 
Reviewed-by: Miroslav Benes 
Acked-by: Peter Zijlstra (Intel) 
Link: https://lkml.kernel.org/r/b811b5eb1a42602c3b523576dc5efab9ad1c174d.1585761021.git.jpoimboe@redhat.com
Signed-off-by: Sasha Levin

objtool: Fix CONFIG_UBSAN_TRAP unreachable warnings

2020-05-02T06:48:57+00:00

[ Upstream commit bd841d6154f5f41f8a32d3c1b0bc229e326e640a ]

CONFIG_UBSAN_TRAP causes GCC to emit a UD2 whenever it encounters an
unreachable code path.  This includes __builtin_unreachable().  Because
the BUG() macro uses __builtin_unreachable() after it emits its own UD2,
this results in a double UD2.  In this case objtool rightfully detects
that the second UD2 is unreachable:

  init/main.o: warning: objtool: repair_env_string()+0x1c8: unreachable instruction

We weren't able to figure out a way to get rid of the double UD2s, so
just silence the warning.

Reported-by: Randy Dunlap 
Signed-off-by: Josh Poimboeuf 
Signed-off-by: Borislav Petkov 
Reviewed-by: Kees Cook 
Reviewed-by: Miroslav Benes 
Acked-by: Peter Zijlstra (Intel) 
Link: https://lkml.kernel.org/r/6653ad73c6b59c049211bd7c11ed3809c20ee9f5.1585761021.git.jpoimboe@redhat.com
Signed-off-by: Sasha Levin

libbpf: Initialize *nl_pid so gcc 10 is happy

2020-05-02T06:48:55+00:00

[ Upstream commit 4734b0fefbbf98f8c119eb8344efa19dac82cd2c ]

Builds of Fedora's kernel-tools package started to fail with "may be
used uninitialized" warnings for nl_pid in bpf_set_link_xdp_fd() and
bpf_get_link_xdp_info() on the s390 architecture.

Although libbpf_netlink_open() always returns a negative number when it
does not set *nl_pid, the compiler does not determine this and thus
believes the variable might be used uninitialized. Assuage gcc's fears
by explicitly initializing nl_pid.

Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=1807781

Signed-off-by: Jeremy Cline 
Signed-off-by: Daniel Borkmann 
Acked-by: Andrii Nakryiko 
Link: https://lore.kernel.org/bpf/20200404051430.698058-1-jcline@redhat.com
Signed-off-by: Sasha Levin

bpf: Forbid XADD on spilled pointers for unprivileged users

2020-05-02T06:48:46+00:00

commit 6e7e63cbb023976d828cdb22422606bf77baa8a9 upstream.

When check_xadd() verifies an XADD operation on a pointer to a stack slot
containing a spilled pointer, check_stack_read() verifies that the read,
which is part of XADD, is valid. However, since the placeholder value -1 is
passed as `value_regno`, check_stack_read() can only return a binary
decision and can't return the type of the value that was read. The intent
here is to verify whether the value read from the stack slot may be used as
a SCALAR_VALUE; but since check_stack_read() doesn't check the type, and
the type information is lost when check_stack_read() returns, this is not
enforced, and a malicious user can abuse XADD to leak spilled kernel
pointers.

Fix it by letting check_stack_read() verify that the value is usable as a
SCALAR_VALUE if no type information is passed to the caller.

To be able to use __is_pointer_value() in check_stack_read(), move it up.

Fix up the expected unprivileged error message for a BPF selftest that,
until now, assumed that unprivileged users can use XADD on stack-spilled
pointers. This also gives us a test for the behavior introduced in this
patch for free.

In theory, this could also be fixed by forbidding XADD on stack spills
entirely, since XADD is a locked operation (for operations on memory with
concurrency) and there can't be any concurrency on the BPF stack; but
Alexei has said that he wants to keep XADD on stack slots working to avoid
changes to the test suite [1].

The following BPF program demonstrates how to leak a BPF map pointer as an
unprivileged user using this bug:

    // r7 = map_pointer
    BPF_LD_MAP_FD(BPF_REG_7, small_map),
    // r8 = launder(map_pointer)
    BPF_STX_MEM(BPF_DW, BPF_REG_FP, BPF_REG_7, -8),
    BPF_MOV64_IMM(BPF_REG_1, 0),
    ((struct bpf_insn) {
      .code  = BPF_STX | BPF_DW | BPF_XADD,
      .dst_reg = BPF_REG_FP,
      .src_reg = BPF_REG_1,
      .off = -8
    }),
    BPF_LDX_MEM(BPF_DW, BPF_REG_8, BPF_REG_FP, -8),

    // store r8 into map
    BPF_MOV64_REG(BPF_REG_ARG1, BPF_REG_7),
    BPF_MOV64_REG(BPF_REG_ARG2, BPF_REG_FP),
    BPF_ALU64_IMM(BPF_ADD, BPF_REG_ARG2, -4),
    BPF_ST_MEM(BPF_W, BPF_REG_ARG2, 0, 0),
    BPF_EMIT_CALL(BPF_FUNC_map_lookup_elem),
    BPF_JMP_IMM(BPF_JNE, BPF_REG_0, 0, 1),
    BPF_EXIT_INSN(),
    BPF_STX_MEM(BPF_DW, BPF_REG_0, BPF_REG_8, 0),

    BPF_MOV64_IMM(BPF_REG_0, 0),
    BPF_EXIT_INSN()

[1] https://lore.kernel.org/bpf/20200416211116.qxqcza5vo2ddnkdq@ast-mbp.dhcp.thefacebook.com/

Fixes: 17a5267067f3 ("bpf: verifier (add verifier core)")
Signed-off-by: Jann Horn 
Signed-off-by: Alexei Starovoitov 
Link: https://lore.kernel.org/bpf/20200417000007.10734-1-jannh@google.com
Signed-off-by: Greg Kroah-Hartman

tools/vm: fix cross-compile build

2020-04-29T14:33:15+00:00

commit cf01699ee220c38099eb3e43ce3d10690c8b7060 upstream.

Commit 7ed1c1901fe5 ("tools: fix cross-compile var clobbering") moved
the setup of the CC variable to tools/scripts/Makefile.include to make
the behavior consistent across all the tools Makefiles.

As the vm tools missed the include we end up with the wrong CC in a
cross-compiling evironment.

Fixes: 7ed1c1901fe5 (tools: fix cross-compile var clobbering)
Signed-off-by: Lucas Stach 
Signed-off-by: Andrew Morton 
Cc: Martin Kelly 
Cc: 
Link: http://lkml.kernel.org/r/20200416104748.25243-1-l.stach@pengutronix.de
Signed-off-by: Linus Torvalds 
Signed-off-by: Greg Kroah-Hartman