<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux-stable.git/kernel/trace, branch v5.10.147</title>
<subtitle>Linux kernel stable tree</subtitle>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/'/>
<entry>
<title>tracing: hold caller_addr to hardirq_{enable,disable}_ip</title>
<updated>2022-09-23T12:16:58+00:00</updated>
<author>
<name>Yipeng Zou</name>
<email>zouyipeng@huawei.com</email>
</author>
<published>2022-09-01T10:45:14+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=6a27acda3d6a8b388ca87868b30e1fcb05e2c18f'/>
<id>6a27acda3d6a8b388ca87868b30e1fcb05e2c18f</id>
<content type='text'>
[ Upstream commit 54c3931957f6a6194d5972eccc36d052964b2abe ]

Currently, The arguments passing to lockdep_hardirqs_{on,off} was fixed
in CALLER_ADDR0.
The function trace_hardirqs_on_caller should have been intended to use
caller_addr to represent the address that caller wants to be traced.

For example, lockdep log in riscv showing the last {enabled,disabled} at
__trace_hardirqs_{on,off} all the time(if called by):
[   57.853175] hardirqs last  enabled at (2519): __trace_hardirqs_on+0xc/0x14
[   57.853848] hardirqs last disabled at (2520): __trace_hardirqs_off+0xc/0x14

After use trace_hardirqs_xx_caller, we can get more effective information:
[   53.781428] hardirqs last  enabled at (2595): restore_all+0xe/0x66
[   53.782185] hardirqs last disabled at (2596): ret_from_exception+0xa/0x10

Link: https://lkml.kernel.org/r/20220901104515.135162-2-zouyipeng@huawei.com

Cc: stable@vger.kernel.org
Fixes: c3bc8fd637a96 ("tracing: Centralize preemptirq tracepoints and unify their usage")
Signed-off-by: Yipeng Zou &lt;zouyipeng@huawei.com&gt;
Signed-off-by: Steven Rostedt (Google) &lt;rostedt@goodmis.org&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit 54c3931957f6a6194d5972eccc36d052964b2abe ]

Currently, The arguments passing to lockdep_hardirqs_{on,off} was fixed
in CALLER_ADDR0.
The function trace_hardirqs_on_caller should have been intended to use
caller_addr to represent the address that caller wants to be traced.

For example, lockdep log in riscv showing the last {enabled,disabled} at
__trace_hardirqs_{on,off} all the time(if called by):
[   57.853175] hardirqs last  enabled at (2519): __trace_hardirqs_on+0xc/0x14
[   57.853848] hardirqs last disabled at (2520): __trace_hardirqs_off+0xc/0x14

After use trace_hardirqs_xx_caller, we can get more effective information:
[   53.781428] hardirqs last  enabled at (2595): restore_all+0xe/0x66
[   53.782185] hardirqs last disabled at (2596): ret_from_exception+0xa/0x10

Link: https://lkml.kernel.org/r/20220901104515.135162-2-zouyipeng@huawei.com

Cc: stable@vger.kernel.org
Fixes: c3bc8fd637a96 ("tracing: Centralize preemptirq tracepoints and unify their usage")
Signed-off-by: Yipeng Zou &lt;zouyipeng@huawei.com&gt;
Signed-off-by: Steven Rostedt (Google) &lt;rostedt@goodmis.org&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>ftrace: Fix NULL pointer dereference in is_ftrace_trampoline when ftrace is dead</title>
<updated>2022-09-05T08:28:56+00:00</updated>
<author>
<name>Yang Jihong</name>
<email>yangjihong1@huawei.com</email>
</author>
<published>2022-08-18T03:26:59+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=dbd8c8fc60480e3faa3ae7e27ebe03371ecd1b77'/>
<id>dbd8c8fc60480e3faa3ae7e27ebe03371ecd1b77</id>
<content type='text'>
commit c3b0f72e805f0801f05fa2aa52011c4bfc694c44 upstream.

ftrace_startup does not remove ops from ftrace_ops_list when
ftrace_startup_enable fails:

register_ftrace_function
  ftrace_startup
    __register_ftrace_function
      ...
      add_ftrace_ops(&amp;ftrace_ops_list, ops)
      ...
    ...
    ftrace_startup_enable // if ftrace failed to modify, ftrace_disabled is set to 1
    ...
  return 0 // ops is in the ftrace_ops_list.

When ftrace_disabled = 1, unregister_ftrace_function simply returns without doing anything:
unregister_ftrace_function
  ftrace_shutdown
    if (unlikely(ftrace_disabled))
            return -ENODEV;  // return here, __unregister_ftrace_function is not executed,
                             // as a result, ops is still in the ftrace_ops_list
    __unregister_ftrace_function
    ...

If ops is dynamically allocated, it will be free later, in this case,
is_ftrace_trampoline accesses NULL pointer:

is_ftrace_trampoline
  ftrace_ops_trampoline
    do_for_each_ftrace_op(op, ftrace_ops_list) // OOPS! op may be NULL!

Syzkaller reports as follows:
[ 1203.506103] BUG: kernel NULL pointer dereference, address: 000000000000010b
[ 1203.508039] #PF: supervisor read access in kernel mode
[ 1203.508798] #PF: error_code(0x0000) - not-present page
[ 1203.509558] PGD 800000011660b067 P4D 800000011660b067 PUD 130fb8067 PMD 0
[ 1203.510560] Oops: 0000 [#1] SMP KASAN PTI
[ 1203.511189] CPU: 6 PID: 29532 Comm: syz-executor.2 Tainted: G    B   W         5.10.0 #8
[ 1203.512324] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.14.0-0-g155821a1990b-prebuilt.qemu.org 04/01/2014
[ 1203.513895] RIP: 0010:is_ftrace_trampoline+0x26/0xb0
[ 1203.514644] Code: ff eb d3 90 41 55 41 54 49 89 fc 55 53 e8 f2 00 fd ff 48 8b 1d 3b 35 5d 03 e8 e6 00 fd ff 48 8d bb 90 00 00 00 e8 2a 81 26 00 &lt;48&gt; 8b ab 90 00 00 00 48 85 ed 74 1d e8 c9 00 fd ff 48 8d bb 98 00
[ 1203.518838] RSP: 0018:ffffc900012cf960 EFLAGS: 00010246
[ 1203.520092] RAX: 0000000000000000 RBX: 000000000000007b RCX: ffffffff8a331866
[ 1203.521469] RDX: 0000000000000000 RSI: 0000000000000008 RDI: 000000000000010b
[ 1203.522583] RBP: 0000000000000000 R08: 0000000000000000 R09: ffffffff8df18b07
[ 1203.523550] R10: fffffbfff1be3160 R11: 0000000000000001 R12: 0000000000478399
[ 1203.524596] R13: 0000000000000000 R14: ffff888145088000 R15: 0000000000000008
[ 1203.525634] FS:  00007f429f5f4700(0000) GS:ffff8881daf00000(0000) knlGS:0000000000000000
[ 1203.526801] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 1203.527626] CR2: 000000000000010b CR3: 0000000170e1e001 CR4: 00000000003706e0
[ 1203.528611] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[ 1203.529605] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400

Therefore, when ftrace_startup_enable fails, we need to rollback registration
process and remove ops from ftrace_ops_list.

Link: https://lkml.kernel.org/r/20220818032659.56209-1-yangjihong1@huawei.com

Suggested-by: Steven Rostedt &lt;rostedt@goodmis.org&gt;
Signed-off-by: Yang Jihong &lt;yangjihong1@huawei.com&gt;
Signed-off-by: Steven Rostedt (Google) &lt;rostedt@goodmis.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit c3b0f72e805f0801f05fa2aa52011c4bfc694c44 upstream.

ftrace_startup does not remove ops from ftrace_ops_list when
ftrace_startup_enable fails:

register_ftrace_function
  ftrace_startup
    __register_ftrace_function
      ...
      add_ftrace_ops(&amp;ftrace_ops_list, ops)
      ...
    ...
    ftrace_startup_enable // if ftrace failed to modify, ftrace_disabled is set to 1
    ...
  return 0 // ops is in the ftrace_ops_list.

When ftrace_disabled = 1, unregister_ftrace_function simply returns without doing anything:
unregister_ftrace_function
  ftrace_shutdown
    if (unlikely(ftrace_disabled))
            return -ENODEV;  // return here, __unregister_ftrace_function is not executed,
                             // as a result, ops is still in the ftrace_ops_list
    __unregister_ftrace_function
    ...

If ops is dynamically allocated, it will be free later, in this case,
is_ftrace_trampoline accesses NULL pointer:

is_ftrace_trampoline
  ftrace_ops_trampoline
    do_for_each_ftrace_op(op, ftrace_ops_list) // OOPS! op may be NULL!

Syzkaller reports as follows:
[ 1203.506103] BUG: kernel NULL pointer dereference, address: 000000000000010b
[ 1203.508039] #PF: supervisor read access in kernel mode
[ 1203.508798] #PF: error_code(0x0000) - not-present page
[ 1203.509558] PGD 800000011660b067 P4D 800000011660b067 PUD 130fb8067 PMD 0
[ 1203.510560] Oops: 0000 [#1] SMP KASAN PTI
[ 1203.511189] CPU: 6 PID: 29532 Comm: syz-executor.2 Tainted: G    B   W         5.10.0 #8
[ 1203.512324] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.14.0-0-g155821a1990b-prebuilt.qemu.org 04/01/2014
[ 1203.513895] RIP: 0010:is_ftrace_trampoline+0x26/0xb0
[ 1203.514644] Code: ff eb d3 90 41 55 41 54 49 89 fc 55 53 e8 f2 00 fd ff 48 8b 1d 3b 35 5d 03 e8 e6 00 fd ff 48 8d bb 90 00 00 00 e8 2a 81 26 00 &lt;48&gt; 8b ab 90 00 00 00 48 85 ed 74 1d e8 c9 00 fd ff 48 8d bb 98 00
[ 1203.518838] RSP: 0018:ffffc900012cf960 EFLAGS: 00010246
[ 1203.520092] RAX: 0000000000000000 RBX: 000000000000007b RCX: ffffffff8a331866
[ 1203.521469] RDX: 0000000000000000 RSI: 0000000000000008 RDI: 000000000000010b
[ 1203.522583] RBP: 0000000000000000 R08: 0000000000000000 R09: ffffffff8df18b07
[ 1203.523550] R10: fffffbfff1be3160 R11: 0000000000000001 R12: 0000000000478399
[ 1203.524596] R13: 0000000000000000 R14: ffff888145088000 R15: 0000000000000008
[ 1203.525634] FS:  00007f429f5f4700(0000) GS:ffff8881daf00000(0000) knlGS:0000000000000000
[ 1203.526801] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 1203.527626] CR2: 000000000000010b CR3: 0000000170e1e001 CR4: 00000000003706e0
[ 1203.528611] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[ 1203.529605] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400

Therefore, when ftrace_startup_enable fails, we need to rollback registration
process and remove ops from ftrace_ops_list.

Link: https://lkml.kernel.org/r/20220818032659.56209-1-yangjihong1@huawei.com

Suggested-by: Steven Rostedt &lt;rostedt@goodmis.org&gt;
Signed-off-by: Yang Jihong &lt;yangjihong1@huawei.com&gt;
Signed-off-by: Steven Rostedt (Google) &lt;rostedt@goodmis.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>tracing/probes: Have kprobes and uprobes use $COMM too</title>
<updated>2022-08-25T09:38:23+00:00</updated>
<author>
<name>Steven Rostedt (Google)</name>
<email>rostedt@goodmis.org</email>
</author>
<published>2022-08-20T13:43:21+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=184e73f12cbad9ccad80a390c7731e8c09598225'/>
<id>184e73f12cbad9ccad80a390c7731e8c09598225</id>
<content type='text'>
commit ab8384442ee512fc0fc72deeb036110843d0e7ff upstream.

Both $comm and $COMM can be used to get current-&gt;comm in eprobes and the
filtering and histogram logic. Make kprobes and uprobes consistent in this
regard and allow both $comm and $COMM as well. Currently kprobes and
uprobes only handle $comm, which is inconsistent with the other utilities,
and can be confusing to users.

Link: https://lkml.kernel.org/r/20220820134401.317014913@goodmis.org
Link: https://lore.kernel.org/all/20220820220442.776e1ddaf8836e82edb34d01@kernel.org/

Cc: stable@vger.kernel.org
Cc: Ingo Molnar &lt;mingo@kernel.org&gt;
Cc: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Cc: Tzvetomir Stoyanov &lt;tz.stoyanov@gmail.com&gt;
Cc: Tom Zanussi &lt;zanussi@kernel.org&gt;
Fixes: 533059281ee5 ("tracing: probeevent: Introduce new argument fetching code")
Suggested-by: Masami Hiramatsu (Google) &lt;mhiramat@kernel.org&gt;
Acked-by: Masami Hiramatsu (Google) &lt;mhiramat@kernel.org&gt;
Signed-off-by: Steven Rostedt (Google) &lt;rostedt@goodmis.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit ab8384442ee512fc0fc72deeb036110843d0e7ff upstream.

Both $comm and $COMM can be used to get current-&gt;comm in eprobes and the
filtering and histogram logic. Make kprobes and uprobes consistent in this
regard and allow both $comm and $COMM as well. Currently kprobes and
uprobes only handle $comm, which is inconsistent with the other utilities,
and can be confusing to users.

Link: https://lkml.kernel.org/r/20220820134401.317014913@goodmis.org
Link: https://lore.kernel.org/all/20220820220442.776e1ddaf8836e82edb34d01@kernel.org/

Cc: stable@vger.kernel.org
Cc: Ingo Molnar &lt;mingo@kernel.org&gt;
Cc: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Cc: Tzvetomir Stoyanov &lt;tz.stoyanov@gmail.com&gt;
Cc: Tom Zanussi &lt;zanussi@kernel.org&gt;
Fixes: 533059281ee5 ("tracing: probeevent: Introduce new argument fetching code")
Suggested-by: Masami Hiramatsu (Google) &lt;mhiramat@kernel.org&gt;
Acked-by: Masami Hiramatsu (Google) &lt;mhiramat@kernel.org&gt;
Signed-off-by: Steven Rostedt (Google) &lt;rostedt@goodmis.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>tracing: Have filter accept "common_cpu" to be consistent</title>
<updated>2022-08-25T09:37:51+00:00</updated>
<author>
<name>Steven Rostedt (Google)</name>
<email>rostedt@goodmis.org</email>
</author>
<published>2022-08-20T13:43:22+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=5d3b02b80d9307b6e70977ce716a4219dd995668'/>
<id>5d3b02b80d9307b6e70977ce716a4219dd995668</id>
<content type='text'>
commit b2380577d4fe1c0ef3fa50417f1e441c016e4cbe upstream.

Make filtering consistent with histograms. As "cpu" can be a field of an
event, allow for "common_cpu" to keep it from being confused with the
"cpu" field of the event.

Link: https://lkml.kernel.org/r/20220820134401.513062765@goodmis.org
Link: https://lore.kernel.org/all/20220820220920.e42fa32b70505b1904f0a0ad@kernel.org/

Cc: stable@vger.kernel.org
Cc: Ingo Molnar &lt;mingo@kernel.org&gt;
Cc: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Cc: Tzvetomir Stoyanov &lt;tz.stoyanov@gmail.com&gt;
Cc: Tom Zanussi &lt;zanussi@kernel.org&gt;
Fixes: 1e3bac71c5053 ("tracing/histogram: Rename "cpu" to "common_cpu"")
Suggested-by: Masami Hiramatsu (Google) &lt;mhiramat@kernel.org&gt;
Acked-by: Masami Hiramatsu (Google) &lt;mhiramat@kernel.org&gt;
Signed-off-by: Steven Rostedt (Google) &lt;rostedt@goodmis.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit b2380577d4fe1c0ef3fa50417f1e441c016e4cbe upstream.

Make filtering consistent with histograms. As "cpu" can be a field of an
event, allow for "common_cpu" to keep it from being confused with the
"cpu" field of the event.

Link: https://lkml.kernel.org/r/20220820134401.513062765@goodmis.org
Link: https://lore.kernel.org/all/20220820220920.e42fa32b70505b1904f0a0ad@kernel.org/

Cc: stable@vger.kernel.org
Cc: Ingo Molnar &lt;mingo@kernel.org&gt;
Cc: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Cc: Tzvetomir Stoyanov &lt;tz.stoyanov@gmail.com&gt;
Cc: Tom Zanussi &lt;zanussi@kernel.org&gt;
Fixes: 1e3bac71c5053 ("tracing/histogram: Rename "cpu" to "common_cpu"")
Suggested-by: Masami Hiramatsu (Google) &lt;mhiramat@kernel.org&gt;
Acked-by: Masami Hiramatsu (Google) &lt;mhiramat@kernel.org&gt;
Signed-off-by: Steven Rostedt (Google) &lt;rostedt@goodmis.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>blktrace: Trace remapped requests correctly</title>
<updated>2022-08-21T13:15:36+00:00</updated>
<author>
<name>Bart Van Assche</name>
<email>bvanassche@acm.org</email>
</author>
<published>2022-07-14T18:06:36+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=1ed71e6bcedbbf40e19c2c808df9d2e5891a7314'/>
<id>1ed71e6bcedbbf40e19c2c808df9d2e5891a7314</id>
<content type='text'>
[ Upstream commit 22c80aac882f712897b88b7ea8f5a74ea19019df ]

Trace the remapped operation and its flags instead of only the data
direction of remapped operations. This issue was detected by analyzing
the warnings reported by sparse related to the new blk_opf_t type.

Reviewed-by: Jun'ichi Nomura &lt;junichi.nomura@nec.com&gt;
Cc: Mike Snitzer &lt;snitzer@kernel.org&gt;
Cc: Mike Christie &lt;michael.christie@oracle.com&gt;
Cc: Li Zefan &lt;lizf@cn.fujitsu.com&gt;
Cc: Chaitanya Kulkarni &lt;kch@nvidia.com&gt;
Fixes: 1b9a9ab78b0a ("blktrace: use op accessors")
Signed-off-by: Bart Van Assche &lt;bvanassche@acm.org&gt;
Link: https://lore.kernel.org/r/20220714180729.1065367-11-bvanassche@acm.org
Signed-off-by: Jens Axboe &lt;axboe@kernel.dk&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit 22c80aac882f712897b88b7ea8f5a74ea19019df ]

Trace the remapped operation and its flags instead of only the data
direction of remapped operations. This issue was detected by analyzing
the warnings reported by sparse related to the new blk_opf_t type.

Reviewed-by: Jun'ichi Nomura &lt;junichi.nomura@nec.com&gt;
Cc: Mike Snitzer &lt;snitzer@kernel.org&gt;
Cc: Mike Christie &lt;michael.christie@oracle.com&gt;
Cc: Li Zefan &lt;lizf@cn.fujitsu.com&gt;
Cc: Chaitanya Kulkarni &lt;kch@nvidia.com&gt;
Fixes: 1b9a9ab78b0a ("blktrace: use op accessors")
Signed-off-by: Bart Van Assche &lt;bvanassche@acm.org&gt;
Link: https://lore.kernel.org/r/20220714180729.1065367-11-bvanassche@acm.org
Signed-off-by: Jens Axboe &lt;axboe@kernel.dk&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>block: remove the request_queue to argument request based tracepoints</title>
<updated>2022-08-21T13:15:36+00:00</updated>
<author>
<name>Christoph Hellwig</name>
<email>hch@lst.de</email>
</author>
<published>2020-12-03T16:21:39+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=1cb3032406423b25aa984854b4d78e0100d292dd'/>
<id>1cb3032406423b25aa984854b4d78e0100d292dd</id>
<content type='text'>
[ Upstream commit a54895fa057c67700270777f7661d8d3c7fda88a ]

The request_queue can trivially be derived from the request.

Signed-off-by: Christoph Hellwig &lt;hch@lst.de&gt;
Reviewed-by: Damien Le Moal &lt;damien.lemoal@wdc.com&gt;
Reviewed-by: Hannes Reinecke &lt;hare@suse.de&gt;
Reviewed-by: Chaitanya Kulkarni &lt;chaitanya.kulkarni@wdc.com&gt;
Acked-by: Tejun Heo &lt;tj@kernel.org&gt;
Signed-off-by: Jens Axboe &lt;axboe@kernel.dk&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit a54895fa057c67700270777f7661d8d3c7fda88a ]

The request_queue can trivially be derived from the request.

Signed-off-by: Christoph Hellwig &lt;hch@lst.de&gt;
Reviewed-by: Damien Le Moal &lt;damien.lemoal@wdc.com&gt;
Reviewed-by: Hannes Reinecke &lt;hare@suse.de&gt;
Reviewed-by: Chaitanya Kulkarni &lt;chaitanya.kulkarni@wdc.com&gt;
Acked-by: Tejun Heo &lt;tj@kernel.org&gt;
Signed-off-by: Jens Axboe &lt;axboe@kernel.dk&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>tracing/histograms: Fix memory leak problem</title>
<updated>2022-07-21T19:19:59+00:00</updated>
<author>
<name>Zheng Yejian</name>
<email>zhengyejian1@huawei.com</email>
</author>
<published>2022-07-11T01:47:31+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=78a1400c42ee11197eb1f0f85ba51df9a4fdfff0'/>
<id>78a1400c42ee11197eb1f0f85ba51df9a4fdfff0</id>
<content type='text'>
commit 7edc3945bdce9c39198a10d6129377a5c53559c2 upstream.

This reverts commit 46bbe5c671e06f070428b9be142cc4ee5cedebac.

As commit 46bbe5c671e0 ("tracing: fix double free") said, the
"double free" problem reported by clang static analyzer is:
  &gt; In parse_var_defs() if there is a problem allocating
  &gt; var_defs.expr, the earlier var_defs.name is freed.
  &gt; This free is duplicated by free_var_defs() which frees
  &gt; the rest of the list.

However, if there is a problem allocating N-th var_defs.expr:
  + in parse_var_defs(), the freed 'earlier var_defs.name' is
    actually the N-th var_defs.name;
  + then in free_var_defs(), the names from 0th to (N-1)-th are freed;

                        IF ALLOCATING PROBLEM HAPPENED HERE!!! -+
                                                                 \
                                                                  |
          0th           1th                 (N-1)-th      N-th    V
          +-------------+-------------+-----+-------------+-----------
var_defs: | name | expr | name | expr | ... | name | expr | name | ///
          +-------------+-------------+-----+-------------+-----------

These two frees don't act on same name, so there was no "double free"
problem before. Conversely, after that commit, we get a "memory leak"
problem because the above "N-th var_defs.name" is not freed.

If enable CONFIG_DEBUG_KMEMLEAK and inject a fault at where the N-th
var_defs.expr allocated, then execute on shell like:
  $ echo 'hist:key=call_site:val=$v1,$v2:v1=bytes_req,v2=bytes_alloc' &gt; \
/sys/kernel/debug/tracing/events/kmem/kmalloc/trigger

Then kmemleak reports:
  unreferenced object 0xffff8fb100ef3518 (size 8):
    comm "bash", pid 196, jiffies 4295681690 (age 28.538s)
    hex dump (first 8 bytes):
      76 31 00 00 b1 8f ff ff                          v1......
    backtrace:
      [&lt;0000000038fe4895&gt;] kstrdup+0x2d/0x60
      [&lt;00000000c99c049a&gt;] event_hist_trigger_parse+0x206f/0x20e0
      [&lt;00000000ae70d2cc&gt;] trigger_process_regex+0xc0/0x110
      [&lt;0000000066737a4c&gt;] event_trigger_write+0x75/0xd0
      [&lt;000000007341e40c&gt;] vfs_write+0xbb/0x2a0
      [&lt;0000000087fde4c2&gt;] ksys_write+0x59/0xd0
      [&lt;00000000581e9cdf&gt;] do_syscall_64+0x3a/0x80
      [&lt;00000000cf3b065c&gt;] entry_SYSCALL_64_after_hwframe+0x46/0xb0

Link: https://lkml.kernel.org/r/20220711014731.69520-1-zhengyejian1@huawei.com

Cc: stable@vger.kernel.org
Fixes: 46bbe5c671e0 ("tracing: fix double free")
Reported-by: Hulk Robot &lt;hulkci@huawei.com&gt;
Suggested-by: Steven Rostedt &lt;rostedt@goodmis.org&gt;
Reviewed-by: Tom Zanussi &lt;tom.zanussi@linux.intel.com&gt;
Signed-off-by: Zheng Yejian &lt;zhengyejian1@huawei.com&gt;
Signed-off-by: Steven Rostedt (Google) &lt;rostedt@goodmis.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit 7edc3945bdce9c39198a10d6129377a5c53559c2 upstream.

This reverts commit 46bbe5c671e06f070428b9be142cc4ee5cedebac.

As commit 46bbe5c671e0 ("tracing: fix double free") said, the
"double free" problem reported by clang static analyzer is:
  &gt; In parse_var_defs() if there is a problem allocating
  &gt; var_defs.expr, the earlier var_defs.name is freed.
  &gt; This free is duplicated by free_var_defs() which frees
  &gt; the rest of the list.

However, if there is a problem allocating N-th var_defs.expr:
  + in parse_var_defs(), the freed 'earlier var_defs.name' is
    actually the N-th var_defs.name;
  + then in free_var_defs(), the names from 0th to (N-1)-th are freed;

                        IF ALLOCATING PROBLEM HAPPENED HERE!!! -+
                                                                 \
                                                                  |
          0th           1th                 (N-1)-th      N-th    V
          +-------------+-------------+-----+-------------+-----------
var_defs: | name | expr | name | expr | ... | name | expr | name | ///
          +-------------+-------------+-----+-------------+-----------

These two frees don't act on same name, so there was no "double free"
problem before. Conversely, after that commit, we get a "memory leak"
problem because the above "N-th var_defs.name" is not freed.

If enable CONFIG_DEBUG_KMEMLEAK and inject a fault at where the N-th
var_defs.expr allocated, then execute on shell like:
  $ echo 'hist:key=call_site:val=$v1,$v2:v1=bytes_req,v2=bytes_alloc' &gt; \
/sys/kernel/debug/tracing/events/kmem/kmalloc/trigger

Then kmemleak reports:
  unreferenced object 0xffff8fb100ef3518 (size 8):
    comm "bash", pid 196, jiffies 4295681690 (age 28.538s)
    hex dump (first 8 bytes):
      76 31 00 00 b1 8f ff ff                          v1......
    backtrace:
      [&lt;0000000038fe4895&gt;] kstrdup+0x2d/0x60
      [&lt;00000000c99c049a&gt;] event_hist_trigger_parse+0x206f/0x20e0
      [&lt;00000000ae70d2cc&gt;] trigger_process_regex+0xc0/0x110
      [&lt;0000000066737a4c&gt;] event_trigger_write+0x75/0xd0
      [&lt;000000007341e40c&gt;] vfs_write+0xbb/0x2a0
      [&lt;0000000087fde4c2&gt;] ksys_write+0x59/0xd0
      [&lt;00000000581e9cdf&gt;] do_syscall_64+0x3a/0x80
      [&lt;00000000cf3b065c&gt;] entry_SYSCALL_64_after_hwframe+0x46/0xb0

Link: https://lkml.kernel.org/r/20220711014731.69520-1-zhengyejian1@huawei.com

Cc: stable@vger.kernel.org
Fixes: 46bbe5c671e0 ("tracing: fix double free")
Reported-by: Hulk Robot &lt;hulkci@huawei.com&gt;
Suggested-by: Steven Rostedt &lt;rostedt@goodmis.org&gt;
Reviewed-by: Tom Zanussi &lt;tom.zanussi@linux.intel.com&gt;
Signed-off-by: Zheng Yejian &lt;zhengyejian1@huawei.com&gt;
Signed-off-by: Steven Rostedt (Google) &lt;rostedt@goodmis.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>tracing: Avoid adding tracer option before update_tracer_options</title>
<updated>2022-06-14T16:32:38+00:00</updated>
<author>
<name>Mark-PK Tsai</name>
<email>mark-pk.tsai@mediatek.com</email>
</author>
<published>2022-04-26T12:24:06+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=9e801c891aa2a002aa2b4259459c1d09f24e75b9'/>
<id>9e801c891aa2a002aa2b4259459c1d09f24e75b9</id>
<content type='text'>
[ Upstream commit ef9188bcc6ca1d8a2ad83e826b548e6820721061 ]

To prepare for support asynchronous tracer_init_tracefs initcall,
avoid calling create_trace_option_files before __update_tracer_options.
Otherwise, create_trace_option_files will show warning because
some tracers in trace_types list are already in tr-&gt;topts.

For example, hwlat_tracer call register_tracer in late_initcall,
and global_trace.dir is already created in tracing_init_dentry,
hwlat_tracer will be put into tr-&gt;topts.
Then if the __update_tracer_options is executed after hwlat_tracer
registered, create_trace_option_files find that hwlat_tracer is
already in tr-&gt;topts.

Link: https://lkml.kernel.org/r/20220426122407.17042-2-mark-pk.tsai@mediatek.com

Link: https://lore.kernel.org/lkml/20220322133339.GA32582@xsang-OptiPlex-9020/
Reported-by: kernel test robot &lt;oliver.sang@intel.com&gt;
Signed-off-by: Mark-PK Tsai &lt;mark-pk.tsai@mediatek.com&gt;
Signed-off-by: Steven Rostedt (Google) &lt;rostedt@goodmis.org&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit ef9188bcc6ca1d8a2ad83e826b548e6820721061 ]

To prepare for support asynchronous tracer_init_tracefs initcall,
avoid calling create_trace_option_files before __update_tracer_options.
Otherwise, create_trace_option_files will show warning because
some tracers in trace_types list are already in tr-&gt;topts.

For example, hwlat_tracer call register_tracer in late_initcall,
and global_trace.dir is already created in tracing_init_dentry,
hwlat_tracer will be put into tr-&gt;topts.
Then if the __update_tracer_options is executed after hwlat_tracer
registered, create_trace_option_files find that hwlat_tracer is
already in tr-&gt;topts.

Link: https://lkml.kernel.org/r/20220426122407.17042-2-mark-pk.tsai@mediatek.com

Link: https://lore.kernel.org/lkml/20220322133339.GA32582@xsang-OptiPlex-9020/
Reported-by: kernel test robot &lt;oliver.sang@intel.com&gt;
Signed-off-by: Mark-PK Tsai &lt;mark-pk.tsai@mediatek.com&gt;
Signed-off-by: Steven Rostedt (Google) &lt;rostedt@goodmis.org&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>tracing: Fix sleeping function called from invalid context on RT kernel</title>
<updated>2022-06-14T16:32:37+00:00</updated>
<author>
<name>Jun Miao</name>
<email>jun.miao@intel.com</email>
</author>
<published>2022-04-19T01:39:10+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=1788e6dbb61286215442b1af99e51405a6206762'/>
<id>1788e6dbb61286215442b1af99e51405a6206762</id>
<content type='text'>
[ Upstream commit 12025abdc8539ed9d5014e2d647a3fd1bd3de5cd ]

When setting bootparams="trace_event=initcall:initcall_start tp_printk=1" in the
cmdline, the output_printk() was called, and the spin_lock_irqsave() was called in the
atomic and irq disable interrupt context suitation. On the PREEMPT_RT kernel,
these locks are replaced with sleepable rt-spinlock, so the stack calltrace will
be triggered.
Fix it by raw_spin_lock_irqsave when PREEMPT_RT and "trace_event=initcall:initcall_start
tp_printk=1" enabled.

 BUG: sleeping function called from invalid context at kernel/locking/spinlock_rt.c:46
 in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 1, name: swapper/0
 preempt_count: 2, expected: 0
 RCU nest depth: 0, expected: 0
 Preemption disabled at:
 [&lt;ffffffff8992303e&gt;] try_to_wake_up+0x7e/0xba0
 CPU: 0 PID: 1 Comm: swapper/0 Not tainted 5.17.1-rt17+ #19 34c5812404187a875f32bee7977f7367f9679ea7
 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.14.0-2 04/01/2014
 Call Trace:
  &lt;TASK&gt;
  dump_stack_lvl+0x60/0x8c
  dump_stack+0x10/0x12
  __might_resched.cold+0x11d/0x155
  rt_spin_lock+0x40/0x70
  trace_event_buffer_commit+0x2fa/0x4c0
  ? map_vsyscall+0x93/0x93
  trace_event_raw_event_initcall_start+0xbe/0x110
  ? perf_trace_initcall_finish+0x210/0x210
  ? probe_sched_wakeup+0x34/0x40
  ? ttwu_do_wakeup+0xda/0x310
  ? trace_hardirqs_on+0x35/0x170
  ? map_vsyscall+0x93/0x93
  do_one_initcall+0x217/0x3c0
  ? trace_event_raw_event_initcall_level+0x170/0x170
  ? push_cpu_stop+0x400/0x400
  ? cblist_init_generic+0x241/0x290
  kernel_init_freeable+0x1ac/0x347
  ? _raw_spin_unlock_irq+0x65/0x80
  ? rest_init+0xf0/0xf0
  kernel_init+0x1e/0x150
  ret_from_fork+0x22/0x30
  &lt;/TASK&gt;

Link: https://lkml.kernel.org/r/20220419013910.894370-1-jun.miao@intel.com

Signed-off-by: Jun Miao &lt;jun.miao@intel.com&gt;
Signed-off-by: Steven Rostedt (Google) &lt;rostedt@goodmis.org&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit 12025abdc8539ed9d5014e2d647a3fd1bd3de5cd ]

When setting bootparams="trace_event=initcall:initcall_start tp_printk=1" in the
cmdline, the output_printk() was called, and the spin_lock_irqsave() was called in the
atomic and irq disable interrupt context suitation. On the PREEMPT_RT kernel,
these locks are replaced with sleepable rt-spinlock, so the stack calltrace will
be triggered.
Fix it by raw_spin_lock_irqsave when PREEMPT_RT and "trace_event=initcall:initcall_start
tp_printk=1" enabled.

 BUG: sleeping function called from invalid context at kernel/locking/spinlock_rt.c:46
 in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 1, name: swapper/0
 preempt_count: 2, expected: 0
 RCU nest depth: 0, expected: 0
 Preemption disabled at:
 [&lt;ffffffff8992303e&gt;] try_to_wake_up+0x7e/0xba0
 CPU: 0 PID: 1 Comm: swapper/0 Not tainted 5.17.1-rt17+ #19 34c5812404187a875f32bee7977f7367f9679ea7
 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.14.0-2 04/01/2014
 Call Trace:
  &lt;TASK&gt;
  dump_stack_lvl+0x60/0x8c
  dump_stack+0x10/0x12
  __might_resched.cold+0x11d/0x155
  rt_spin_lock+0x40/0x70
  trace_event_buffer_commit+0x2fa/0x4c0
  ? map_vsyscall+0x93/0x93
  trace_event_raw_event_initcall_start+0xbe/0x110
  ? perf_trace_initcall_finish+0x210/0x210
  ? probe_sched_wakeup+0x34/0x40
  ? ttwu_do_wakeup+0xda/0x310
  ? trace_hardirqs_on+0x35/0x170
  ? map_vsyscall+0x93/0x93
  do_one_initcall+0x217/0x3c0
  ? trace_event_raw_event_initcall_level+0x170/0x170
  ? push_cpu_stop+0x400/0x400
  ? cblist_init_generic+0x241/0x290
  kernel_init_freeable+0x1ac/0x347
  ? _raw_spin_unlock_irq+0x65/0x80
  ? rest_init+0xf0/0xf0
  kernel_init+0x1e/0x150
  ret_from_fork+0x22/0x30
  &lt;/TASK&gt;

Link: https://lkml.kernel.org/r/20220419013910.894370-1-jun.miao@intel.com

Signed-off-by: Jun Miao &lt;jun.miao@intel.com&gt;
Signed-off-by: Steven Rostedt (Google) &lt;rostedt@goodmis.org&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>ftrace: Clean up hash direct_functions on register failures</title>
<updated>2022-06-09T08:21:26+00:00</updated>
<author>
<name>Song Liu</name>
<email>song@kernel.org</email>
</author>
<published>2022-05-24T17:08:39+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=82c888e51c2176a06f8b4541cf748ee81aac6e7e'/>
<id>82c888e51c2176a06f8b4541cf748ee81aac6e7e</id>
<content type='text'>
commit 7d54c15cb89a29a5f59e5ffc9ee62e6591769ef1 upstream.

We see the following GPF when register_ftrace_direct fails:

[ ] general protection fault, probably for non-canonical address \
  0x200000000000010: 0000 [#1] PREEMPT SMP DEBUG_PAGEALLOC PTI
[...]
[ ] RIP: 0010:ftrace_find_rec_direct+0x53/0x70
[ ] Code: 48 c1 e0 03 48 03 42 08 48 8b 10 31 c0 48 85 d2 74 [...]
[ ] RSP: 0018:ffffc9000138bc10 EFLAGS: 00010206
[ ] RAX: 0000000000000000 RBX: ffffffff813e0df0 RCX: 000000000000003b
[ ] RDX: 0200000000000000 RSI: 000000000000000c RDI: ffffffff813e0df0
[ ] RBP: ffffffffa00a3000 R08: ffffffff81180ce0 R09: 0000000000000001
[ ] R10: ffffc9000138bc18 R11: 0000000000000001 R12: ffffffff813e0df0
[ ] R13: ffffffff813e0df0 R14: ffff888171b56400 R15: 0000000000000000
[ ] FS:  00007fa9420c7780(0000) GS:ffff888ff6a00000(0000) knlGS:000000000
[ ] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ ] CR2: 000000000770d000 CR3: 0000000107d50003 CR4: 0000000000370ee0
[ ] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[ ] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[ ] Call Trace:
[ ]  &lt;TASK&gt;
[ ]  register_ftrace_direct+0x54/0x290
[ ]  ? render_sigset_t+0xa0/0xa0
[ ]  bpf_trampoline_update+0x3f5/0x4a0
[ ]  ? 0xffffffffa00a3000
[ ]  bpf_trampoline_link_prog+0xa9/0x140
[ ]  bpf_tracing_prog_attach+0x1dc/0x450
[ ]  bpf_raw_tracepoint_open+0x9a/0x1e0
[ ]  ? find_held_lock+0x2d/0x90
[ ]  ? lock_release+0x150/0x430
[ ]  __sys_bpf+0xbd6/0x2700
[ ]  ? lock_is_held_type+0xd8/0x130
[ ]  __x64_sys_bpf+0x1c/0x20
[ ]  do_syscall_64+0x3a/0x80
[ ]  entry_SYSCALL_64_after_hwframe+0x44/0xae
[ ] RIP: 0033:0x7fa9421defa9
[ ] Code: 00 c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 9 f8 [...]
[ ] RSP: 002b:00007ffed743bd78 EFLAGS: 00000246 ORIG_RAX: 0000000000000141
[ ] RAX: ffffffffffffffda RBX: 00000000069d2480 RCX: 00007fa9421defa9
[ ] RDX: 0000000000000078 RSI: 00007ffed743bd80 RDI: 0000000000000011
[ ] RBP: 00007ffed743be00 R08: 0000000000bb7270 R09: 0000000000000000
[ ] R10: 00000000069da210 R11: 0000000000000246 R12: 0000000000000001
[ ] R13: 00007ffed743c4b0 R14: 00000000069d2480 R15: 0000000000000001
[ ]  &lt;/TASK&gt;
[ ] Modules linked in: klp_vm(OK)
[ ] ---[ end trace 0000000000000000 ]---

One way to trigger this is:
  1. load a livepatch that patches kernel function xxx;
  2. run bpftrace -e 'kfunc:xxx {}', this will fail (expected for now);
  3. repeat #2 =&gt; gpf.

This is because the entry is added to direct_functions, but not removed.
Fix this by remove the entry from direct_functions when
register_ftrace_direct fails.

Also remove the last trailing space from ftrace.c, so we don't have to
worry about it anymore.

Link: https://lkml.kernel.org/r/20220524170839.900849-1-song@kernel.org

Cc: stable@vger.kernel.org
Fixes: 763e34e74bb7 ("ftrace: Add register_ftrace_direct()")
Signed-off-by: Song Liu &lt;song@kernel.org&gt;
Signed-off-by: Steven Rostedt (Google) &lt;rostedt@goodmis.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit 7d54c15cb89a29a5f59e5ffc9ee62e6591769ef1 upstream.

We see the following GPF when register_ftrace_direct fails:

[ ] general protection fault, probably for non-canonical address \
  0x200000000000010: 0000 [#1] PREEMPT SMP DEBUG_PAGEALLOC PTI
[...]
[ ] RIP: 0010:ftrace_find_rec_direct+0x53/0x70
[ ] Code: 48 c1 e0 03 48 03 42 08 48 8b 10 31 c0 48 85 d2 74 [...]
[ ] RSP: 0018:ffffc9000138bc10 EFLAGS: 00010206
[ ] RAX: 0000000000000000 RBX: ffffffff813e0df0 RCX: 000000000000003b
[ ] RDX: 0200000000000000 RSI: 000000000000000c RDI: ffffffff813e0df0
[ ] RBP: ffffffffa00a3000 R08: ffffffff81180ce0 R09: 0000000000000001
[ ] R10: ffffc9000138bc18 R11: 0000000000000001 R12: ffffffff813e0df0
[ ] R13: ffffffff813e0df0 R14: ffff888171b56400 R15: 0000000000000000
[ ] FS:  00007fa9420c7780(0000) GS:ffff888ff6a00000(0000) knlGS:000000000
[ ] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ ] CR2: 000000000770d000 CR3: 0000000107d50003 CR4: 0000000000370ee0
[ ] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[ ] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[ ] Call Trace:
[ ]  &lt;TASK&gt;
[ ]  register_ftrace_direct+0x54/0x290
[ ]  ? render_sigset_t+0xa0/0xa0
[ ]  bpf_trampoline_update+0x3f5/0x4a0
[ ]  ? 0xffffffffa00a3000
[ ]  bpf_trampoline_link_prog+0xa9/0x140
[ ]  bpf_tracing_prog_attach+0x1dc/0x450
[ ]  bpf_raw_tracepoint_open+0x9a/0x1e0
[ ]  ? find_held_lock+0x2d/0x90
[ ]  ? lock_release+0x150/0x430
[ ]  __sys_bpf+0xbd6/0x2700
[ ]  ? lock_is_held_type+0xd8/0x130
[ ]  __x64_sys_bpf+0x1c/0x20
[ ]  do_syscall_64+0x3a/0x80
[ ]  entry_SYSCALL_64_after_hwframe+0x44/0xae
[ ] RIP: 0033:0x7fa9421defa9
[ ] Code: 00 c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 9 f8 [...]
[ ] RSP: 002b:00007ffed743bd78 EFLAGS: 00000246 ORIG_RAX: 0000000000000141
[ ] RAX: ffffffffffffffda RBX: 00000000069d2480 RCX: 00007fa9421defa9
[ ] RDX: 0000000000000078 RSI: 00007ffed743bd80 RDI: 0000000000000011
[ ] RBP: 00007ffed743be00 R08: 0000000000bb7270 R09: 0000000000000000
[ ] R10: 00000000069da210 R11: 0000000000000246 R12: 0000000000000001
[ ] R13: 00007ffed743c4b0 R14: 00000000069d2480 R15: 0000000000000001
[ ]  &lt;/TASK&gt;
[ ] Modules linked in: klp_vm(OK)
[ ] ---[ end trace 0000000000000000 ]---

One way to trigger this is:
  1. load a livepatch that patches kernel function xxx;
  2. run bpftrace -e 'kfunc:xxx {}', this will fail (expected for now);
  3. repeat #2 =&gt; gpf.

This is because the entry is added to direct_functions, but not removed.
Fix this by remove the entry from direct_functions when
register_ftrace_direct fails.

Also remove the last trailing space from ftrace.c, so we don't have to
worry about it anymore.

Link: https://lkml.kernel.org/r/20220524170839.900849-1-song@kernel.org

Cc: stable@vger.kernel.org
Fixes: 763e34e74bb7 ("ftrace: Add register_ftrace_direct()")
Signed-off-by: Song Liu &lt;song@kernel.org&gt;
Signed-off-by: Steven Rostedt (Google) &lt;rostedt@goodmis.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
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