linux-stable.git/kernel, branch v5.8.13

kprobes: tracing/kprobes: Fix to kill kprobes on initmem after boot

2020-10-01T15:36:33+00:00

commit 82d083ab60c3693201c6f5c7a5f23a6ed422098d upstream.

Since kprobe_event= cmdline option allows user to put kprobes on the
functions in initmem, kprobe has to make such probes gone after boot.
Currently the probes on the init functions in modules will be handled
by module callback, but the kernel init text isn't handled.
Without this, kprobes may access non-exist text area to disable or
remove it.

Link: https://lkml.kernel.org/r/159972810544.428528.1839307531600646955.stgit@devnote2

Fixes: 970988e19eb0 ("tracing/kprobe: Add kprobe_event= boot parameter")
Cc: Jonathan Corbet 
Cc: Shuah Khan 
Cc: Randy Dunlap 
Cc: Ingo Molnar 
Cc: stable@vger.kernel.org
Signed-off-by: Masami Hiramatsu 
Signed-off-by: Steven Rostedt (VMware) 
Signed-off-by: Greg Kroah-Hartman

kprobes: Fix to check probe enabled before disarm_kprobe_ftrace()

2020-10-01T15:36:33+00:00

commit 3031313eb3d549b7ad6f9fbcc52ba04412e3eb9e upstream.

Commit 0cb2f1372baa ("kprobes: Fix NULL pointer dereference at
kprobe_ftrace_handler") fixed one bug but not completely fixed yet.
If we run a kprobe_module.tc of ftracetest, kernel showed a warning
as below.

# ./ftracetest test.d/kprobe/kprobe_module.tc
=== Ftrace unit tests ===
[1] Kprobe dynamic event - probing module
...
[   22.400215] ------------[ cut here ]------------
[   22.400962] Failed to disarm kprobe-ftrace at trace_printk_irq_work+0x0/0x7e [trace_printk] (-2)
[   22.402139] WARNING: CPU: 7 PID: 200 at kernel/kprobes.c:1091 __disarm_kprobe_ftrace.isra.0+0x7e/0xa0
[   22.403358] Modules linked in: trace_printk(-)
[   22.404028] CPU: 7 PID: 200 Comm: rmmod Not tainted 5.9.0-rc2+ #66
[   22.404870] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.13.0-1ubuntu1 04/01/2014
[   22.406139] RIP: 0010:__disarm_kprobe_ftrace.isra.0+0x7e/0xa0
[   22.406947] Code: 30 8b 03 eb c9 80 3d e5 09 1f 01 00 75 dc 49 8b 34 24 89 c2 48 c7 c7 a0 c2 05 82 89 45 e4 c6 05 cc 09 1f 01 01 e8 a9 c7 f0 ff <0f> 0b 8b 45 e4 eb b9 89 c6 48 c7 c7 70 c2 05 82 89 45 e4 e8 91 c7
[   22.409544] RSP: 0018:ffffc90000237df0 EFLAGS: 00010286
[   22.410385] RAX: 0000000000000000 RBX: ffffffff83066024 RCX: 0000000000000000
[   22.411434] RDX: 0000000000000001 RSI: ffffffff810de8d3 RDI: ffffffff810de8d3
[   22.412687] RBP: ffffc90000237e10 R08: 0000000000000001 R09: 0000000000000001
[   22.413762] R10: 0000000000000000 R11: 0000000000000001 R12: ffff88807c478640
[   22.414852] R13: ffffffff8235ebc0 R14: ffffffffa00060c0 R15: 0000000000000000
[   22.415941] FS:  00000000019d48c0(0000) GS:ffff88807d7c0000(0000) knlGS:0000000000000000
[   22.417264] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[   22.418176] CR2: 00000000005bb7e3 CR3: 0000000078f7a000 CR4: 00000000000006a0
[   22.419309] Call Trace:
[   22.419990]  kill_kprobe+0x94/0x160
[   22.420652]  kprobes_module_callback+0x64/0x230
[   22.421470]  notifier_call_chain+0x4f/0x70
[   22.422184]  blocking_notifier_call_chain+0x49/0x70
[   22.422979]  __x64_sys_delete_module+0x1ac/0x240
[   22.423733]  do_syscall_64+0x38/0x50
[   22.424366]  entry_SYSCALL_64_after_hwframe+0x44/0xa9
[   22.425176] RIP: 0033:0x4bb81d
[   22.425741] Code: 00 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 c7 c1 e0 ff ff ff f7 d8 64 89 01 48
[   22.428726] RSP: 002b:00007ffc70fef008 EFLAGS: 00000246 ORIG_RAX: 00000000000000b0
[   22.430169] RAX: ffffffffffffffda RBX: 00000000019d48a0 RCX: 00000000004bb81d
[   22.431375] RDX: 0000000000000000 RSI: 0000000000000880 RDI: 00007ffc70fef028
[   22.432543] RBP: 0000000000000880 R08: 00000000ffffffff R09: 00007ffc70fef320
[   22.433692] R10: 0000000000656300 R11: 0000000000000246 R12: 00007ffc70fef028
[   22.434635] R13: 0000000000000000 R14: 0000000000000002 R15: 0000000000000000
[   22.435682] irq event stamp: 1169
[   22.436240] hardirqs last  enabled at (1179): [] console_unlock+0x422/0x580
[   22.437466] hardirqs last disabled at (1188): [] console_unlock+0x7b/0x580
[   22.438608] softirqs last  enabled at (866): [] __do_softirq+0x38e/0x490
[   22.439637] softirqs last disabled at (859): [] asm_call_on_stack+0x12/0x20
[   22.440690] ---[ end trace 1e7ce7e1e4567276 ]---
[   22.472832] trace_kprobe: This probe might be able to register after target module is loaded. Continue.

This is because the kill_kprobe() calls disarm_kprobe_ftrace() even
if the given probe is not enabled. In that case, ftrace_set_filter_ip()
fails because the given probe point is not registered to ftrace.

Fix to check the given (going) probe is enabled before invoking
disarm_kprobe_ftrace().

Link: https://lkml.kernel.org/r/159888672694.1411785.5987998076694782591.stgit@devnote2

Fixes: 0cb2f1372baa ("kprobes: Fix NULL pointer dereference at kprobe_ftrace_handler")
Cc: Ingo Molnar 
Cc: "Naveen N . Rao" 
Cc: Anil S Keshavamurthy 
Cc: David Miller 
Cc: Muchun Song 
Cc: Chengming Zhou 
Cc: stable@vger.kernel.org
Signed-off-by: Masami Hiramatsu 
Signed-off-by: Steven Rostedt (VMware) 
Signed-off-by: Greg Kroah-Hartman

tracing: fix double free

2020-10-01T15:36:33+00:00

commit 46bbe5c671e06f070428b9be142cc4ee5cedebac upstream.

clang static analyzer reports this problem

trace_events_hist.c:3824:3: warning: Attempt to free
  released memory
    kfree(hist_data->attrs->var_defs.name[i]);

In parse_var_defs() if there is a problem allocating
var_defs.expr, the earlier var_defs.name is freed.
This free is duplicated by free_var_defs() which frees
the rest of the list.

Because free_var_defs() has to run anyway, remove the
second free fom parse_var_defs().

Link: https://lkml.kernel.org/r/20200907135845.15804-1-trix@redhat.com

Cc: stable@vger.kernel.org
Fixes: 30350d65ac56 ("tracing: Add variable support to hist triggers")
Reviewed-by: Tom Zanussi 
Signed-off-by: Tom Rix 
Signed-off-by: Steven Rostedt (VMware) 
Signed-off-by: Greg Kroah-Hartman

bpf: Fix a rcu warning for bpffs map pretty-print

2020-10-01T15:36:29+00:00

[ Upstream commit ce880cb825fcc22d4e39046a6c3a3a7f6603883d ]

Running selftest
  ./btf_btf -p
the kernel had the following warning:
  [   51.528185] WARNING: CPU: 3 PID: 1756 at kernel/bpf/hashtab.c:717 htab_map_get_next_key+0x2eb/0x300
  [   51.529217] Modules linked in:
  [   51.529583] CPU: 3 PID: 1756 Comm: test_btf Not tainted 5.9.0-rc1+ #878
  [   51.530346] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.9.3-1.el7.centos 04/01/2014
  [   51.531410] RIP: 0010:htab_map_get_next_key+0x2eb/0x300
  ...
  [   51.542826] Call Trace:
  [   51.543119]  map_seq_next+0x53/0x80
  [   51.543528]  seq_read+0x263/0x400
  [   51.543932]  vfs_read+0xad/0x1c0
  [   51.544311]  ksys_read+0x5f/0xe0
  [   51.544689]  do_syscall_64+0x33/0x40
  [   51.545116]  entry_SYSCALL_64_after_hwframe+0x44/0xa9

The related source code in kernel/bpf/hashtab.c:
  709 static int htab_map_get_next_key(struct bpf_map *map, void *key, void *next_key)
  710 {
  711         struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
  712         struct hlist_nulls_head *head;
  713         struct htab_elem *l, *next_l;
  714         u32 hash, key_size;
  715         int i = 0;
  716
  717         WARN_ON_ONCE(!rcu_read_lock_held());

In kernel/bpf/inode.c, bpffs map pretty print calls map->ops->map_get_next_key()
without holding a rcu_read_lock(), hence causing the above warning.
To fix the issue, just surrounding map->ops->map_get_next_key() with rcu read lock.

Fixes: a26ca7c982cb ("bpf: btf: Add pretty print support to the basic arraymap")
Reported-by: Alexei Starovoitov 
Signed-off-by: Yonghong Song 
Signed-off-by: Alexei Starovoitov 
Acked-by: Andrii Nakryiko 
Cc: Martin KaFai Lau 
Link: https://lore.kernel.org/bpf/20200916004401.146277-1-yhs@fb.com
Signed-off-by: Sasha Levin

lockdep: fix order in trace_hardirqs_off_caller()

2020-10-01T15:36:24+00:00

[ Upstream commit 73ac74c7d489756d2313219a108809921dbfaea1 ]

Switch order so that locking state is consistent even
if the IRQ tracer calls into lockdep again.

Acked-by: Peter Zijlstra 
Signed-off-by: Sven Schnelle 
Signed-off-by: Vasily Gorbik 
Signed-off-by: Sasha Levin

kprobes: fix kill kprobe which has been marked as gone

2020-09-23T11:00:01+00:00

commit b0399092ccebd9feef68d4ceb8d6219a8c0caa05 upstream.

If a kprobe is marked as gone, we should not kill it again.  Otherwise, we
can disarm the kprobe more than once.  In that case, the statistics of
kprobe_ftrace_enabled can unbalance which can lead to that kprobe do not
work.

Fixes: e8386a0cb22f ("kprobes: support probing module __exit function")
Co-developed-by: Chengming Zhou 
Signed-off-by: Muchun Song 
Signed-off-by: Chengming Zhou 
Signed-off-by: Andrew Morton 
Acked-by: Masami Hiramatsu 
Cc: "Naveen N . Rao" 
Cc: Anil S Keshavamurthy 
Cc: David S. Miller 
Cc: Song Liu 
Cc: Steven Rostedt 
Cc: 
Link: https://lkml.kernel.org/r/20200822030055.32383-1-songmuchun@bytedance.com
Signed-off-by: Linus Torvalds 
Signed-off-by: Greg Kroah-Hartman

locking/percpu-rwsem: Use this_cpu_{inc,dec}() for read_count

2020-09-23T10:59:58+00:00

[ Upstream commit e6b1a44eccfcab5e5e280be376f65478c3b2c7a2 ]

The __this_cpu*() accessors are (in general) IRQ-unsafe which, given
that percpu-rwsem is a blocking primitive, should be just fine.

However, file_end_write() is used from IRQ context and will cause
load-store issues on architectures where the per-cpu accessors are not
natively irq-safe.

Fix it by using the IRQ-safe this_cpu_*() for operations on
read_count. This will generate more expensive code on a number of
platforms, which might cause a performance regression for some of the
other percpu-rwsem users.

If any such is reported, we can consider alternative solutions.

Fixes: 70fe2f48152e ("aio: fix freeze protection of aio writes")
Signed-off-by: Hou Tao 
Signed-off-by: Peter Zijlstra (Intel) 
Acked-by: Will Deacon 
Acked-by: Oleg Nesterov 
Link: https://lkml.kernel.org/r/20200915140750.137881-1-houtao1@huawei.com
Signed-off-by: Sasha Levin

locking/lockdep: Fix "USED" <- "IN-NMI" inversions

2020-09-23T10:59:58+00:00

[ Upstream commit 23870f1227680d2aacff6f79c3ab2222bd04e86e ]

During the LPC RCU BoF Paul asked how come the "USED" <- "IN-NMI"
detector doesn't trip over rcu_read_lock()'s lockdep annotation.

Looking into this I found a very embarrasing typo in
verify_lock_unused():

	-	if (!(class->usage_mask & LOCK_USED))
	+	if (!(class->usage_mask & LOCKF_USED))

fixing that will indeed cause rcu_read_lock() to insta-splat :/

The above typo means that instead of testing for: 0x100 (1 <<
LOCK_USED), we test for 8 (LOCK_USED), which corresponds to (1 <<
LOCK_ENABLED_HARDIRQ).

So instead of testing for _any_ used lock, it will only match any lock
used with interrupts enabled.

The rcu_read_lock() annotation uses .check=0, which means it will not
set any of the interrupt bits and will thus never match.

In order to properly fix the situation and allow rcu_read_lock() to
correctly work, split LOCK_USED into LOCK_USED and LOCK_USED_READ and by
having .read users set USED_READ and test USED, pure read-recursive
locks are permitted.

Fixes: f6f48e180404 ("lockdep: Teach lockdep about "USED" <- "IN-NMI" inversions")
Signed-off-by: Peter Zijlstra (Intel) 
Signed-off-by: Ingo Molnar 
Tested-by: Masami Hiramatsu 
Acked-by: Paul E. McKenney 
Link: https://lore.kernel.org/r/20200902160323.GK1362448@hirez.programming.kicks-ass.net
Signed-off-by: Sasha Levin

gcov: add support for GCC 10.1

2020-09-17T11:55:47+00:00

[ Upstream commit 40249c6962075c040fd071339acae524f18bfac9 ]

Using gcov to collect coverage data for kernels compiled with GCC 10.1
causes random malfunctions and kernel crashes.  This is the result of a
changed GCOV_COUNTERS value in GCC 10.1 that causes a mismatch between
the layout of the gcov_info structure created by GCC profiling code and
the related structure used by the kernel.

Fix this by updating the in-kernel GCOV_COUNTERS value.  Also re-enable
config GCOV_KERNEL for use with GCC 10.

Reported-by: Colin Ian King 
Reported-by: Leon Romanovsky 
Signed-off-by: Peter Oberparleiter 
Tested-by: Leon Romanovsky 
Tested-and-Acked-by: Colin Ian King 
Signed-off-by: Linus Torvalds 
Signed-off-by: Sasha Levin

gcov: Disable gcov build with GCC 10

2020-09-17T11:55:37+00:00

[ Upstream commit cfc905f158eaa099d6258031614d11869e7ef71c ]

GCOV built with GCC 10 doesn't initialize n_function variable.  This
produces different kernel panics as was seen by Colin in Ubuntu and me
in FC 32.

As a workaround, let's disable GCOV build for broken GCC 10 version.

Link: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1891288
Link: https://lore.kernel.org/lkml/20200827133932.3338519-1-leon@kernel.org
Link: https://lore.kernel.org/lkml/CAHk-=whbijeSdSvx-Xcr0DPMj0BiwhJ+uiNnDSVZcr_h_kg7UA@mail.gmail.com/
Cc: Colin Ian King 
Signed-off-by: Leon Romanovsky 
Signed-off-by: Linus Torvalds 
Signed-off-by: Sasha Levin