<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux.git/kernel/trace, branch v5.2-rc6</title>
<subtitle>Linux kernel source tree</subtitle>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/'/>
<entry>
<title>Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net</title>
<updated>2019-06-17T22:55:34+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2019-06-17T22:55:34+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=da0f382029868806e88c046eb2560fdee7a9457c'/>
<id>da0f382029868806e88c046eb2560fdee7a9457c</id>
<content type='text'>
Pull networking fixes from David Miller:
 "Lots of bug fixes here:

   1) Out of bounds access in __bpf_skc_lookup, from Lorenz Bauer.

   2) Fix rate reporting in cfg80211_calculate_bitrate_he(), from John
      Crispin.

   3) Use after free in psock backlog workqueue, from John Fastabend.

   4) Fix source port matching in fdb peer flow rule of mlx5, from Raed
      Salem.

   5) Use atomic_inc_not_zero() in fl6_sock_lookup(), from Eric Dumazet.

   6) Network header needs to be set for packet redirect in nfp, from
      John Hurley.

   7) Fix udp zerocopy refcnt, from Willem de Bruijn.

   8) Don't assume linear buffers in vxlan and geneve error handlers,
      from Stefano Brivio.

   9) Fix TOS matching in mlxsw, from Jiri Pirko.

  10) More SCTP cookie memory leak fixes, from Neil Horman.

  11) Fix VLAN filtering in rtl8366, from Linus Walluij.

  12) Various TCP SACK payload size and fragmentation memory limit fixes
      from Eric Dumazet.

  13) Use after free in pneigh_get_next(), also from Eric Dumazet.

  14) LAPB control block leak fix from Jeremy Sowden"

* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net: (145 commits)
  lapb: fixed leak of control-blocks.
  tipc: purge deferredq list for each grp member in tipc_group_delete
  ax25: fix inconsistent lock state in ax25_destroy_timer
  neigh: fix use-after-free read in pneigh_get_next
  tcp: fix compile error if !CONFIG_SYSCTL
  hv_sock: Suppress bogus "may be used uninitialized" warnings
  be2net: Fix number of Rx queues used for flow hashing
  net: handle 802.1P vlan 0 packets properly
  tcp: enforce tcp_min_snd_mss in tcp_mtu_probing()
  tcp: add tcp_min_snd_mss sysctl
  tcp: tcp_fragment() should apply sane memory limits
  tcp: limit payload size of sacked skbs
  Revert "net: phylink: set the autoneg state in phylink_phy_change"
  bpf: fix nested bpf tracepoints with per-cpu data
  bpf: Fix out of bounds memory access in bpf_sk_storage
  vsock/virtio: set SOCK_DONE on peer shutdown
  net: dsa: rtl8366: Fix up VLAN filtering
  net: phylink: set the autoneg state in phylink_phy_change
  net: add high_order_alloc_disable sysctl/static key
  tcp: add tcp_tx_skb_cache sysctl
  ...
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Pull networking fixes from David Miller:
 "Lots of bug fixes here:

   1) Out of bounds access in __bpf_skc_lookup, from Lorenz Bauer.

   2) Fix rate reporting in cfg80211_calculate_bitrate_he(), from John
      Crispin.

   3) Use after free in psock backlog workqueue, from John Fastabend.

   4) Fix source port matching in fdb peer flow rule of mlx5, from Raed
      Salem.

   5) Use atomic_inc_not_zero() in fl6_sock_lookup(), from Eric Dumazet.

   6) Network header needs to be set for packet redirect in nfp, from
      John Hurley.

   7) Fix udp zerocopy refcnt, from Willem de Bruijn.

   8) Don't assume linear buffers in vxlan and geneve error handlers,
      from Stefano Brivio.

   9) Fix TOS matching in mlxsw, from Jiri Pirko.

  10) More SCTP cookie memory leak fixes, from Neil Horman.

  11) Fix VLAN filtering in rtl8366, from Linus Walluij.

  12) Various TCP SACK payload size and fragmentation memory limit fixes
      from Eric Dumazet.

  13) Use after free in pneigh_get_next(), also from Eric Dumazet.

  14) LAPB control block leak fix from Jeremy Sowden"

* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net: (145 commits)
  lapb: fixed leak of control-blocks.
  tipc: purge deferredq list for each grp member in tipc_group_delete
  ax25: fix inconsistent lock state in ax25_destroy_timer
  neigh: fix use-after-free read in pneigh_get_next
  tcp: fix compile error if !CONFIG_SYSCTL
  hv_sock: Suppress bogus "may be used uninitialized" warnings
  be2net: Fix number of Rx queues used for flow hashing
  net: handle 802.1P vlan 0 packets properly
  tcp: enforce tcp_min_snd_mss in tcp_mtu_probing()
  tcp: add tcp_min_snd_mss sysctl
  tcp: tcp_fragment() should apply sane memory limits
  tcp: limit payload size of sacked skbs
  Revert "net: phylink: set the autoneg state in phylink_phy_change"
  bpf: fix nested bpf tracepoints with per-cpu data
  bpf: Fix out of bounds memory access in bpf_sk_storage
  vsock/virtio: set SOCK_DONE on peer shutdown
  net: dsa: rtl8366: Fix up VLAN filtering
  net: phylink: set the autoneg state in phylink_phy_change
  net: add high_order_alloc_disable sysctl/static key
  tcp: add tcp_tx_skb_cache sysctl
  ...
</pre>
</div>
</content>
</entry>
<entry>
<title>bpf: fix nested bpf tracepoints with per-cpu data</title>
<updated>2019-06-15T23:33:35+00:00</updated>
<author>
<name>Matt Mullins</name>
<email>mmullins@fb.com</email>
</author>
<published>2019-06-11T21:53:04+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=9594dc3c7e71b9f52bee1d7852eb3d4e3aea9e99'/>
<id>9594dc3c7e71b9f52bee1d7852eb3d4e3aea9e99</id>
<content type='text'>
BPF_PROG_TYPE_RAW_TRACEPOINTs can be executed nested on the same CPU, as
they do not increment bpf_prog_active while executing.

This enables three levels of nesting, to support
  - a kprobe or raw tp or perf event,
  - another one of the above that irq context happens to call, and
  - another one in nmi context
(at most one of which may be a kprobe or perf event).

Fixes: 20b9d7ac4852 ("bpf: avoid excessive stack usage for perf_sample_data")
Signed-off-by: Matt Mullins &lt;mmullins@fb.com&gt;
Acked-by: Andrii Nakryiko &lt;andriin@fb.com&gt;
Acked-by: Daniel Borkmann &lt;daniel@iogearbox.net&gt;
Signed-off-by: Alexei Starovoitov &lt;ast@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
BPF_PROG_TYPE_RAW_TRACEPOINTs can be executed nested on the same CPU, as
they do not increment bpf_prog_active while executing.

This enables three levels of nesting, to support
  - a kprobe or raw tp or perf event,
  - another one of the above that irq context happens to call, and
  - another one in nmi context
(at most one of which may be a kprobe or perf event).

Fixes: 20b9d7ac4852 ("bpf: avoid excessive stack usage for perf_sample_data")
Signed-off-by: Matt Mullins &lt;mmullins@fb.com&gt;
Acked-by: Andrii Nakryiko &lt;andriin@fb.com&gt;
Acked-by: Daniel Borkmann &lt;daniel@iogearbox.net&gt;
Signed-off-by: Alexei Starovoitov &lt;ast@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>Merge tag 'trace-v5.2-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace</title>
<updated>2019-06-15T17:24:11+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2019-06-15T17:24:11+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=6a71398c6aead255efe445ea96d52b33f0d5f0b2'/>
<id>6a71398c6aead255efe445ea96d52b33f0d5f0b2</id>
<content type='text'>
Pull tracing fixes from Steven Rostedt:

 - Out of range read of stack trace output

 - Fix for NULL pointer dereference in trace_uprobe_create()

 - Fix to a livepatching / ftrace permission race in the module code

 - Fix for NULL pointer dereference in free_ftrace_func_mapper()

 - A couple of build warning clean ups

* tag 'trace-v5.2-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
  ftrace: Fix NULL pointer dereference in free_ftrace_func_mapper()
  module: Fix livepatch/ftrace module text permissions race
  tracing/uprobe: Fix obsolete comment on trace_uprobe_create()
  tracing/uprobe: Fix NULL pointer dereference in trace_uprobe_create()
  tracing: Make two symbols static
  tracing: avoid build warning with HAVE_NOP_MCOUNT
  tracing: Fix out-of-range read in trace_stack_print()
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Pull tracing fixes from Steven Rostedt:

 - Out of range read of stack trace output

 - Fix for NULL pointer dereference in trace_uprobe_create()

 - Fix to a livepatching / ftrace permission race in the module code

 - Fix for NULL pointer dereference in free_ftrace_func_mapper()

 - A couple of build warning clean ups

* tag 'trace-v5.2-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
  ftrace: Fix NULL pointer dereference in free_ftrace_func_mapper()
  module: Fix livepatch/ftrace module text permissions race
  tracing/uprobe: Fix obsolete comment on trace_uprobe_create()
  tracing/uprobe: Fix NULL pointer dereference in trace_uprobe_create()
  tracing: Make two symbols static
  tracing: avoid build warning with HAVE_NOP_MCOUNT
  tracing: Fix out-of-range read in trace_stack_print()
</pre>
</div>
</content>
</entry>
<entry>
<title>ftrace: Fix NULL pointer dereference in free_ftrace_func_mapper()</title>
<updated>2019-06-14T21:40:21+00:00</updated>
<author>
<name>Wei Li</name>
<email>liwei391@huawei.com</email>
</author>
<published>2019-06-06T03:17:54+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=04e03d9a616c19a47178eaca835358610e63a1dd'/>
<id>04e03d9a616c19a47178eaca835358610e63a1dd</id>
<content type='text'>
The mapper may be NULL when called from register_ftrace_function_probe()
with probe-&gt;data == NULL.

This issue can be reproduced as follow (it may be covered by compiler
optimization sometime):

/ # cat /sys/kernel/debug/tracing/set_ftrace_filter
#### all functions enabled ####
/ # echo foo_bar:dump &gt; /sys/kernel/debug/tracing/set_ftrace_filter
[  206.949100] Unable to handle kernel NULL pointer dereference at virtual address 0000000000000000
[  206.952402] Mem abort info:
[  206.952819]   ESR = 0x96000006
[  206.955326]   Exception class = DABT (current EL), IL = 32 bits
[  206.955844]   SET = 0, FnV = 0
[  206.956272]   EA = 0, S1PTW = 0
[  206.956652] Data abort info:
[  206.957320]   ISV = 0, ISS = 0x00000006
[  206.959271]   CM = 0, WnR = 0
[  206.959938] user pgtable: 4k pages, 48-bit VAs, pgdp=0000000419f3a000
[  206.960483] [0000000000000000] pgd=0000000411a87003, pud=0000000411a83003, pmd=0000000000000000
[  206.964953] Internal error: Oops: 96000006 [#1] SMP
[  206.971122] Dumping ftrace buffer:
[  206.973677]    (ftrace buffer empty)
[  206.975258] Modules linked in:
[  206.976631] Process sh (pid: 281, stack limit = 0x(____ptrval____))
[  206.978449] CPU: 10 PID: 281 Comm: sh Not tainted 5.2.0-rc1+ #17
[  206.978955] Hardware name: linux,dummy-virt (DT)
[  206.979883] pstate: 60000005 (nZCv daif -PAN -UAO)
[  206.980499] pc : free_ftrace_func_mapper+0x2c/0x118
[  206.980874] lr : ftrace_count_free+0x68/0x80
[  206.982539] sp : ffff0000182f3ab0
[  206.983102] x29: ffff0000182f3ab0 x28: ffff8003d0ec1700
[  206.983632] x27: ffff000013054b40 x26: 0000000000000001
[  206.984000] x25: ffff00001385f000 x24: 0000000000000000
[  206.984394] x23: ffff000013453000 x22: ffff000013054000
[  206.984775] x21: 0000000000000000 x20: ffff00001385fe28
[  206.986575] x19: ffff000013872c30 x18: 0000000000000000
[  206.987111] x17: 0000000000000000 x16: 0000000000000000
[  206.987491] x15: ffffffffffffffb0 x14: 0000000000000000
[  206.987850] x13: 000000000017430e x12: 0000000000000580
[  206.988251] x11: 0000000000000000 x10: cccccccccccccccc
[  206.988740] x9 : 0000000000000000 x8 : ffff000013917550
[  206.990198] x7 : ffff000012fac2e8 x6 : ffff000012fac000
[  206.991008] x5 : ffff0000103da588 x4 : 0000000000000001
[  206.991395] x3 : 0000000000000001 x2 : ffff000013872a28
[  206.991771] x1 : 0000000000000000 x0 : 0000000000000000
[  206.992557] Call trace:
[  206.993101]  free_ftrace_func_mapper+0x2c/0x118
[  206.994827]  ftrace_count_free+0x68/0x80
[  206.995238]  release_probe+0xfc/0x1d0
[  206.995555]  register_ftrace_function_probe+0x4a8/0x868
[  206.995923]  ftrace_trace_probe_callback.isra.4+0xb8/0x180
[  206.996330]  ftrace_dump_callback+0x50/0x70
[  206.996663]  ftrace_regex_write.isra.29+0x290/0x3a8
[  206.997157]  ftrace_filter_write+0x44/0x60
[  206.998971]  __vfs_write+0x64/0xf0
[  206.999285]  vfs_write+0x14c/0x2f0
[  206.999591]  ksys_write+0xbc/0x1b0
[  206.999888]  __arm64_sys_write+0x3c/0x58
[  207.000246]  el0_svc_common.constprop.0+0x408/0x5f0
[  207.000607]  el0_svc_handler+0x144/0x1c8
[  207.000916]  el0_svc+0x8/0xc
[  207.003699] Code: aa0003f8 a9025bf5 aa0103f5 f946ea80 (f9400303)
[  207.008388] ---[ end trace 7b6d11b5f542bdf1 ]---
[  207.010126] Kernel panic - not syncing: Fatal exception
[  207.011322] SMP: stopping secondary CPUs
[  207.013956] Dumping ftrace buffer:
[  207.014595]    (ftrace buffer empty)
[  207.015632] Kernel Offset: disabled
[  207.017187] CPU features: 0x002,20006008
[  207.017985] Memory Limit: none
[  207.019825] ---[ end Kernel panic - not syncing: Fatal exception ]---

Link: http://lkml.kernel.org/r/20190606031754.10798-1-liwei391@huawei.com

Signed-off-by: Wei Li &lt;liwei391@huawei.com&gt;
Signed-off-by: Steven Rostedt (VMware) &lt;rostedt@goodmis.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
The mapper may be NULL when called from register_ftrace_function_probe()
with probe-&gt;data == NULL.

This issue can be reproduced as follow (it may be covered by compiler
optimization sometime):

/ # cat /sys/kernel/debug/tracing/set_ftrace_filter
#### all functions enabled ####
/ # echo foo_bar:dump &gt; /sys/kernel/debug/tracing/set_ftrace_filter
[  206.949100] Unable to handle kernel NULL pointer dereference at virtual address 0000000000000000
[  206.952402] Mem abort info:
[  206.952819]   ESR = 0x96000006
[  206.955326]   Exception class = DABT (current EL), IL = 32 bits
[  206.955844]   SET = 0, FnV = 0
[  206.956272]   EA = 0, S1PTW = 0
[  206.956652] Data abort info:
[  206.957320]   ISV = 0, ISS = 0x00000006
[  206.959271]   CM = 0, WnR = 0
[  206.959938] user pgtable: 4k pages, 48-bit VAs, pgdp=0000000419f3a000
[  206.960483] [0000000000000000] pgd=0000000411a87003, pud=0000000411a83003, pmd=0000000000000000
[  206.964953] Internal error: Oops: 96000006 [#1] SMP
[  206.971122] Dumping ftrace buffer:
[  206.973677]    (ftrace buffer empty)
[  206.975258] Modules linked in:
[  206.976631] Process sh (pid: 281, stack limit = 0x(____ptrval____))
[  206.978449] CPU: 10 PID: 281 Comm: sh Not tainted 5.2.0-rc1+ #17
[  206.978955] Hardware name: linux,dummy-virt (DT)
[  206.979883] pstate: 60000005 (nZCv daif -PAN -UAO)
[  206.980499] pc : free_ftrace_func_mapper+0x2c/0x118
[  206.980874] lr : ftrace_count_free+0x68/0x80
[  206.982539] sp : ffff0000182f3ab0
[  206.983102] x29: ffff0000182f3ab0 x28: ffff8003d0ec1700
[  206.983632] x27: ffff000013054b40 x26: 0000000000000001
[  206.984000] x25: ffff00001385f000 x24: 0000000000000000
[  206.984394] x23: ffff000013453000 x22: ffff000013054000
[  206.984775] x21: 0000000000000000 x20: ffff00001385fe28
[  206.986575] x19: ffff000013872c30 x18: 0000000000000000
[  206.987111] x17: 0000000000000000 x16: 0000000000000000
[  206.987491] x15: ffffffffffffffb0 x14: 0000000000000000
[  206.987850] x13: 000000000017430e x12: 0000000000000580
[  206.988251] x11: 0000000000000000 x10: cccccccccccccccc
[  206.988740] x9 : 0000000000000000 x8 : ffff000013917550
[  206.990198] x7 : ffff000012fac2e8 x6 : ffff000012fac000
[  206.991008] x5 : ffff0000103da588 x4 : 0000000000000001
[  206.991395] x3 : 0000000000000001 x2 : ffff000013872a28
[  206.991771] x1 : 0000000000000000 x0 : 0000000000000000
[  206.992557] Call trace:
[  206.993101]  free_ftrace_func_mapper+0x2c/0x118
[  206.994827]  ftrace_count_free+0x68/0x80
[  206.995238]  release_probe+0xfc/0x1d0
[  206.995555]  register_ftrace_function_probe+0x4a8/0x868
[  206.995923]  ftrace_trace_probe_callback.isra.4+0xb8/0x180
[  206.996330]  ftrace_dump_callback+0x50/0x70
[  206.996663]  ftrace_regex_write.isra.29+0x290/0x3a8
[  206.997157]  ftrace_filter_write+0x44/0x60
[  206.998971]  __vfs_write+0x64/0xf0
[  206.999285]  vfs_write+0x14c/0x2f0
[  206.999591]  ksys_write+0xbc/0x1b0
[  206.999888]  __arm64_sys_write+0x3c/0x58
[  207.000246]  el0_svc_common.constprop.0+0x408/0x5f0
[  207.000607]  el0_svc_handler+0x144/0x1c8
[  207.000916]  el0_svc+0x8/0xc
[  207.003699] Code: aa0003f8 a9025bf5 aa0103f5 f946ea80 (f9400303)
[  207.008388] ---[ end trace 7b6d11b5f542bdf1 ]---
[  207.010126] Kernel panic - not syncing: Fatal exception
[  207.011322] SMP: stopping secondary CPUs
[  207.013956] Dumping ftrace buffer:
[  207.014595]    (ftrace buffer empty)
[  207.015632] Kernel Offset: disabled
[  207.017187] CPU features: 0x002,20006008
[  207.017985] Memory Limit: none
[  207.019825] ---[ end Kernel panic - not syncing: Fatal exception ]---

Link: http://lkml.kernel.org/r/20190606031754.10798-1-liwei391@huawei.com

Signed-off-by: Wei Li &lt;liwei391@huawei.com&gt;
Signed-off-by: Steven Rostedt (VMware) &lt;rostedt@goodmis.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>module: Fix livepatch/ftrace module text permissions race</title>
<updated>2019-06-14T21:01:50+00:00</updated>
<author>
<name>Josh Poimboeuf</name>
<email>jpoimboe@redhat.com</email>
</author>
<published>2019-06-14T01:07:22+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=9f255b632bf12c4dd7fc31caee89aa991ef75176'/>
<id>9f255b632bf12c4dd7fc31caee89aa991ef75176</id>
<content type='text'>
It's possible for livepatch and ftrace to be toggling a module's text
permissions at the same time, resulting in the following panic:

  BUG: unable to handle page fault for address: ffffffffc005b1d9
  #PF: supervisor write access in kernel mode
  #PF: error_code(0x0003) - permissions violation
  PGD 3ea0c067 P4D 3ea0c067 PUD 3ea0e067 PMD 3cc13067 PTE 3b8a1061
  Oops: 0003 [#1] PREEMPT SMP PTI
  CPU: 1 PID: 453 Comm: insmod Tainted: G           O  K   5.2.0-rc1-a188339ca5 #1
  Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.12.0-20181126_142135-anatol 04/01/2014
  RIP: 0010:apply_relocate_add+0xbe/0x14c
  Code: fa 0b 74 21 48 83 fa 18 74 38 48 83 fa 0a 75 40 eb 08 48 83 38 00 74 33 eb 53 83 38 00 75 4e 89 08 89 c8 eb 0a 83 38 00 75 43 &lt;89&gt; 08 48 63 c1 48 39 c8 74 2e eb 48 83 38 00 75 32 48 29 c1 89 08
  RSP: 0018:ffffb223c00dbb10 EFLAGS: 00010246
  RAX: ffffffffc005b1d9 RBX: 0000000000000000 RCX: ffffffff8b200060
  RDX: 000000000000000b RSI: 0000004b0000000b RDI: ffff96bdfcd33000
  RBP: ffffb223c00dbb38 R08: ffffffffc005d040 R09: ffffffffc005c1f0
  R10: ffff96bdfcd33c40 R11: ffff96bdfcd33b80 R12: 0000000000000018
  R13: ffffffffc005c1f0 R14: ffffffffc005e708 R15: ffffffff8b2fbc74
  FS:  00007f5f447beba8(0000) GS:ffff96bdff900000(0000) knlGS:0000000000000000
  CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
  CR2: ffffffffc005b1d9 CR3: 000000003cedc002 CR4: 0000000000360ea0
  DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
  DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
  Call Trace:
   klp_init_object_loaded+0x10f/0x219
   ? preempt_latency_start+0x21/0x57
   klp_enable_patch+0x662/0x809
   ? virt_to_head_page+0x3a/0x3c
   ? kfree+0x8c/0x126
   patch_init+0x2ed/0x1000 [livepatch_test02]
   ? 0xffffffffc0060000
   do_one_initcall+0x9f/0x1c5
   ? kmem_cache_alloc_trace+0xc4/0xd4
   ? do_init_module+0x27/0x210
   do_init_module+0x5f/0x210
   load_module+0x1c41/0x2290
   ? fsnotify_path+0x3b/0x42
   ? strstarts+0x2b/0x2b
   ? kernel_read+0x58/0x65
   __do_sys_finit_module+0x9f/0xc3
   ? __do_sys_finit_module+0x9f/0xc3
   __x64_sys_finit_module+0x1a/0x1c
   do_syscall_64+0x52/0x61
   entry_SYSCALL_64_after_hwframe+0x44/0xa9

The above panic occurs when loading two modules at the same time with
ftrace enabled, where at least one of the modules is a livepatch module:

CPU0					CPU1
klp_enable_patch()
  klp_init_object_loaded()
    module_disable_ro()
    					ftrace_module_enable()
					  ftrace_arch_code_modify_post_process()
				    	    set_all_modules_text_ro()
      klp_write_object_relocations()
        apply_relocate_add()
	  *patches read-only code* - BOOM

A similar race exists when toggling ftrace while loading a livepatch
module.

Fix it by ensuring that the livepatch and ftrace code patching
operations -- and their respective permissions changes -- are protected
by the text_mutex.

Link: http://lkml.kernel.org/r/ab43d56ab909469ac5d2520c5d944ad6d4abd476.1560474114.git.jpoimboe@redhat.com

Reported-by: Johannes Erdfelt &lt;johannes@erdfelt.com&gt;
Fixes: 444d13ff10fb ("modules: add ro_after_init support")
Acked-by: Jessica Yu &lt;jeyu@kernel.org&gt;
Reviewed-by: Petr Mladek &lt;pmladek@suse.com&gt;
Reviewed-by: Miroslav Benes &lt;mbenes@suse.cz&gt;
Signed-off-by: Josh Poimboeuf &lt;jpoimboe@redhat.com&gt;
Signed-off-by: Steven Rostedt (VMware) &lt;rostedt@goodmis.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
It's possible for livepatch and ftrace to be toggling a module's text
permissions at the same time, resulting in the following panic:

  BUG: unable to handle page fault for address: ffffffffc005b1d9
  #PF: supervisor write access in kernel mode
  #PF: error_code(0x0003) - permissions violation
  PGD 3ea0c067 P4D 3ea0c067 PUD 3ea0e067 PMD 3cc13067 PTE 3b8a1061
  Oops: 0003 [#1] PREEMPT SMP PTI
  CPU: 1 PID: 453 Comm: insmod Tainted: G           O  K   5.2.0-rc1-a188339ca5 #1
  Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.12.0-20181126_142135-anatol 04/01/2014
  RIP: 0010:apply_relocate_add+0xbe/0x14c
  Code: fa 0b 74 21 48 83 fa 18 74 38 48 83 fa 0a 75 40 eb 08 48 83 38 00 74 33 eb 53 83 38 00 75 4e 89 08 89 c8 eb 0a 83 38 00 75 43 &lt;89&gt; 08 48 63 c1 48 39 c8 74 2e eb 48 83 38 00 75 32 48 29 c1 89 08
  RSP: 0018:ffffb223c00dbb10 EFLAGS: 00010246
  RAX: ffffffffc005b1d9 RBX: 0000000000000000 RCX: ffffffff8b200060
  RDX: 000000000000000b RSI: 0000004b0000000b RDI: ffff96bdfcd33000
  RBP: ffffb223c00dbb38 R08: ffffffffc005d040 R09: ffffffffc005c1f0
  R10: ffff96bdfcd33c40 R11: ffff96bdfcd33b80 R12: 0000000000000018
  R13: ffffffffc005c1f0 R14: ffffffffc005e708 R15: ffffffff8b2fbc74
  FS:  00007f5f447beba8(0000) GS:ffff96bdff900000(0000) knlGS:0000000000000000
  CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
  CR2: ffffffffc005b1d9 CR3: 000000003cedc002 CR4: 0000000000360ea0
  DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
  DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
  Call Trace:
   klp_init_object_loaded+0x10f/0x219
   ? preempt_latency_start+0x21/0x57
   klp_enable_patch+0x662/0x809
   ? virt_to_head_page+0x3a/0x3c
   ? kfree+0x8c/0x126
   patch_init+0x2ed/0x1000 [livepatch_test02]
   ? 0xffffffffc0060000
   do_one_initcall+0x9f/0x1c5
   ? kmem_cache_alloc_trace+0xc4/0xd4
   ? do_init_module+0x27/0x210
   do_init_module+0x5f/0x210
   load_module+0x1c41/0x2290
   ? fsnotify_path+0x3b/0x42
   ? strstarts+0x2b/0x2b
   ? kernel_read+0x58/0x65
   __do_sys_finit_module+0x9f/0xc3
   ? __do_sys_finit_module+0x9f/0xc3
   __x64_sys_finit_module+0x1a/0x1c
   do_syscall_64+0x52/0x61
   entry_SYSCALL_64_after_hwframe+0x44/0xa9

The above panic occurs when loading two modules at the same time with
ftrace enabled, where at least one of the modules is a livepatch module:

CPU0					CPU1
klp_enable_patch()
  klp_init_object_loaded()
    module_disable_ro()
    					ftrace_module_enable()
					  ftrace_arch_code_modify_post_process()
				    	    set_all_modules_text_ro()
      klp_write_object_relocations()
        apply_relocate_add()
	  *patches read-only code* - BOOM

A similar race exists when toggling ftrace while loading a livepatch
module.

Fix it by ensuring that the livepatch and ftrace code patching
operations -- and their respective permissions changes -- are protected
by the text_mutex.

Link: http://lkml.kernel.org/r/ab43d56ab909469ac5d2520c5d944ad6d4abd476.1560474114.git.jpoimboe@redhat.com

Reported-by: Johannes Erdfelt &lt;johannes@erdfelt.com&gt;
Fixes: 444d13ff10fb ("modules: add ro_after_init support")
Acked-by: Jessica Yu &lt;jeyu@kernel.org&gt;
Reviewed-by: Petr Mladek &lt;pmladek@suse.com&gt;
Reviewed-by: Miroslav Benes &lt;mbenes@suse.cz&gt;
Signed-off-by: Josh Poimboeuf &lt;jpoimboe@redhat.com&gt;
Signed-off-by: Steven Rostedt (VMware) &lt;rostedt@goodmis.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>tracing/uprobe: Fix obsolete comment on trace_uprobe_create()</title>
<updated>2019-06-14T21:00:36+00:00</updated>
<author>
<name>Eiichi Tsukata</name>
<email>devel@etsukata.com</email>
</author>
<published>2019-06-14T07:40:26+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=a4158345ec5acb44cc0a9ef4381e0784c1bc7722'/>
<id>a4158345ec5acb44cc0a9ef4381e0784c1bc7722</id>
<content type='text'>
Commit 0597c49c69d5 ("tracing/uprobes: Use dyn_event framework for
uprobe events") cleaned up the usage of trace_uprobe_create(), and the
function has been no longer used for removing uprobe/uretprobe.

Link: http://lkml.kernel.org/r/20190614074026.8045-2-devel@etsukata.com

Reviewed-by: Srikar Dronamraju &lt;srikar@linux.vnet.ibm.com&gt;
Signed-off-by: Eiichi Tsukata &lt;devel@etsukata.com&gt;
Signed-off-by: Steven Rostedt (VMware) &lt;rostedt@goodmis.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Commit 0597c49c69d5 ("tracing/uprobes: Use dyn_event framework for
uprobe events") cleaned up the usage of trace_uprobe_create(), and the
function has been no longer used for removing uprobe/uretprobe.

Link: http://lkml.kernel.org/r/20190614074026.8045-2-devel@etsukata.com

Reviewed-by: Srikar Dronamraju &lt;srikar@linux.vnet.ibm.com&gt;
Signed-off-by: Eiichi Tsukata &lt;devel@etsukata.com&gt;
Signed-off-by: Steven Rostedt (VMware) &lt;rostedt@goodmis.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>tracing/uprobe: Fix NULL pointer dereference in trace_uprobe_create()</title>
<updated>2019-06-14T20:51:14+00:00</updated>
<author>
<name>Eiichi Tsukata</name>
<email>devel@etsukata.com</email>
</author>
<published>2019-06-14T07:40:25+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=f01098c74b5219f3969d4750eeed1a36bfc038e3'/>
<id>f01098c74b5219f3969d4750eeed1a36bfc038e3</id>
<content type='text'>
Just like the case of commit 8b05a3a7503c ("tracing/kprobes: Fix NULL
pointer dereference in trace_kprobe_create()"), writing an incorrectly
formatted string to uprobe_events can trigger NULL pointer dereference.

Reporeducer:

  # echo r &gt; /sys/kernel/debug/tracing/uprobe_events

dmesg:

  BUG: kernel NULL pointer dereference, address: 0000000000000000
  #PF: supervisor read access in kernel mode
  #PF: error_code(0x0000) - not-present page
  PGD 8000000079d12067 P4D 8000000079d12067 PUD 7b7ab067 PMD 0
  Oops: 0000 [#1] PREEMPT SMP PTI
  CPU: 0 PID: 1903 Comm: bash Not tainted 5.2.0-rc3+ #15
  Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.12.0-2.fc30 04/01/2014
  RIP: 0010:strchr+0x0/0x30
  Code: c0 eb 0d 84 c9 74 18 48 83 c0 01 48 39 d0 74 0f 0f b6 0c 07 3a 0c 06 74 ea 19 c0 83 c8 01 c3 31 c0 c3 0f 1f 84 00 00 00 00 00 &lt;0f&gt; b6 07 89 f2 40 38 f0 75 0e eb 13 0f b6 47 01 48 83 c
  RSP: 0018:ffffb55fc0403d10 EFLAGS: 00010293

  RAX: ffff993ffb793400 RBX: 0000000000000000 RCX: ffffffffa4852625
  RDX: 0000000000000000 RSI: 000000000000002f RDI: 0000000000000000
  RBP: ffffb55fc0403dd0 R08: ffff993ffb793400 R09: 0000000000000000
  R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
  R13: ffff993ff9cc1668 R14: 0000000000000001 R15: 0000000000000000
  FS:  00007f30c5147700(0000) GS:ffff993ffda00000(0000) knlGS:0000000000000000
  CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
  CR2: 0000000000000000 CR3: 000000007b628000 CR4: 00000000000006f0
  Call Trace:
   trace_uprobe_create+0xe6/0xb10
   ? __kmalloc_track_caller+0xe6/0x1c0
   ? __kmalloc+0xf0/0x1d0
   ? trace_uprobe_create+0xb10/0xb10
   create_or_delete_trace_uprobe+0x35/0x90
   ? trace_uprobe_create+0xb10/0xb10
   trace_run_command+0x9c/0xb0
   trace_parse_run_command+0xf9/0x1eb
   ? probes_open+0x80/0x80
   __vfs_write+0x43/0x90
   vfs_write+0x14a/0x2a0
   ksys_write+0xa2/0x170
   do_syscall_64+0x7f/0x200
   entry_SYSCALL_64_after_hwframe+0x49/0xbe

Link: http://lkml.kernel.org/r/20190614074026.8045-1-devel@etsukata.com

Cc: stable@vger.kernel.org
Fixes: 0597c49c69d5 ("tracing/uprobes: Use dyn_event framework for uprobe events")
Reviewed-by: Srikar Dronamraju &lt;srikar@linux.vnet.ibm.com&gt;
Signed-off-by: Eiichi Tsukata &lt;devel@etsukata.com&gt;
Signed-off-by: Steven Rostedt (VMware) &lt;rostedt@goodmis.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Just like the case of commit 8b05a3a7503c ("tracing/kprobes: Fix NULL
pointer dereference in trace_kprobe_create()"), writing an incorrectly
formatted string to uprobe_events can trigger NULL pointer dereference.

Reporeducer:

  # echo r &gt; /sys/kernel/debug/tracing/uprobe_events

dmesg:

  BUG: kernel NULL pointer dereference, address: 0000000000000000
  #PF: supervisor read access in kernel mode
  #PF: error_code(0x0000) - not-present page
  PGD 8000000079d12067 P4D 8000000079d12067 PUD 7b7ab067 PMD 0
  Oops: 0000 [#1] PREEMPT SMP PTI
  CPU: 0 PID: 1903 Comm: bash Not tainted 5.2.0-rc3+ #15
  Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.12.0-2.fc30 04/01/2014
  RIP: 0010:strchr+0x0/0x30
  Code: c0 eb 0d 84 c9 74 18 48 83 c0 01 48 39 d0 74 0f 0f b6 0c 07 3a 0c 06 74 ea 19 c0 83 c8 01 c3 31 c0 c3 0f 1f 84 00 00 00 00 00 &lt;0f&gt; b6 07 89 f2 40 38 f0 75 0e eb 13 0f b6 47 01 48 83 c
  RSP: 0018:ffffb55fc0403d10 EFLAGS: 00010293

  RAX: ffff993ffb793400 RBX: 0000000000000000 RCX: ffffffffa4852625
  RDX: 0000000000000000 RSI: 000000000000002f RDI: 0000000000000000
  RBP: ffffb55fc0403dd0 R08: ffff993ffb793400 R09: 0000000000000000
  R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
  R13: ffff993ff9cc1668 R14: 0000000000000001 R15: 0000000000000000
  FS:  00007f30c5147700(0000) GS:ffff993ffda00000(0000) knlGS:0000000000000000
  CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
  CR2: 0000000000000000 CR3: 000000007b628000 CR4: 00000000000006f0
  Call Trace:
   trace_uprobe_create+0xe6/0xb10
   ? __kmalloc_track_caller+0xe6/0x1c0
   ? __kmalloc+0xf0/0x1d0
   ? trace_uprobe_create+0xb10/0xb10
   create_or_delete_trace_uprobe+0x35/0x90
   ? trace_uprobe_create+0xb10/0xb10
   trace_run_command+0x9c/0xb0
   trace_parse_run_command+0xf9/0x1eb
   ? probes_open+0x80/0x80
   __vfs_write+0x43/0x90
   vfs_write+0x14a/0x2a0
   ksys_write+0xa2/0x170
   do_syscall_64+0x7f/0x200
   entry_SYSCALL_64_after_hwframe+0x49/0xbe

Link: http://lkml.kernel.org/r/20190614074026.8045-1-devel@etsukata.com

Cc: stable@vger.kernel.org
Fixes: 0597c49c69d5 ("tracing/uprobes: Use dyn_event framework for uprobe events")
Reviewed-by: Srikar Dronamraju &lt;srikar@linux.vnet.ibm.com&gt;
Signed-off-by: Eiichi Tsukata &lt;devel@etsukata.com&gt;
Signed-off-by: Steven Rostedt (VMware) &lt;rostedt@goodmis.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>tracing: Make two symbols static</title>
<updated>2019-06-14T20:49:26+00:00</updated>
<author>
<name>YueHaibing</name>
<email>yuehaibing@huawei.com</email>
</author>
<published>2019-06-14T15:32:10+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=ff585c5b9a27e64084c84e2ddf24fd00bf8dcfc1'/>
<id>ff585c5b9a27e64084c84e2ddf24fd00bf8dcfc1</id>
<content type='text'>
Fix sparse warnings:

kernel/trace/trace.c:6927:24: warning:
 symbol 'get_tracing_log_err' was not declared. Should it be static?
kernel/trace/trace.c:8196:15: warning:
 symbol 'trace_instance_dir' was not declared. Should it be static?

Link: http://lkml.kernel.org/r/20190614153210.24424-1-yuehaibing@huawei.com

Acked-by: Tom Zanussi &lt;tom.zanussi@linux.intel.com&gt;
Reported-by: Hulk Robot &lt;hulkci@huawei.com&gt;
Signed-off-by: YueHaibing &lt;yuehaibing@huawei.com&gt;
Signed-off-by: Steven Rostedt (VMware) &lt;rostedt@goodmis.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Fix sparse warnings:

kernel/trace/trace.c:6927:24: warning:
 symbol 'get_tracing_log_err' was not declared. Should it be static?
kernel/trace/trace.c:8196:15: warning:
 symbol 'trace_instance_dir' was not declared. Should it be static?

Link: http://lkml.kernel.org/r/20190614153210.24424-1-yuehaibing@huawei.com

Acked-by: Tom Zanussi &lt;tom.zanussi@linux.intel.com&gt;
Reported-by: Hulk Robot &lt;hulkci@huawei.com&gt;
Signed-off-by: YueHaibing &lt;yuehaibing@huawei.com&gt;
Signed-off-by: Steven Rostedt (VMware) &lt;rostedt@goodmis.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>tracing: avoid build warning with HAVE_NOP_MCOUNT</title>
<updated>2019-06-14T20:34:57+00:00</updated>
<author>
<name>Vasily Gorbik</name>
<email>gor@linux.ibm.com</email>
</author>
<published>2019-06-05T11:11:58+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=cbdaeaf050b730ea02e9ab4ff844ce54d85dbe1d'/>
<id>cbdaeaf050b730ea02e9ab4ff844ce54d85dbe1d</id>
<content type='text'>
Selecting HAVE_NOP_MCOUNT enables -mnop-mcount (if gcc supports it)
and sets CC_USING_NOP_MCOUNT. Reuse __is_defined (which is suitable for
testing CC_USING_* defines) to avoid conditional compilation and fix
the following gcc 9 warning on s390:

kernel/trace/ftrace.c:2514:1: warning: ‘ftrace_code_disable’ defined
but not used [-Wunused-function]

Link: http://lkml.kernel.org/r/patch.git-1a82d13f33ac.your-ad-here.call-01559732716-ext-6629@work.hours

Fixes: 2f4df0017baed ("tracing: Add -mcount-nop option support")
Signed-off-by: Vasily Gorbik &lt;gor@linux.ibm.com&gt;
Signed-off-by: Steven Rostedt (VMware) &lt;rostedt@goodmis.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Selecting HAVE_NOP_MCOUNT enables -mnop-mcount (if gcc supports it)
and sets CC_USING_NOP_MCOUNT. Reuse __is_defined (which is suitable for
testing CC_USING_* defines) to avoid conditional compilation and fix
the following gcc 9 warning on s390:

kernel/trace/ftrace.c:2514:1: warning: ‘ftrace_code_disable’ defined
but not used [-Wunused-function]

Link: http://lkml.kernel.org/r/patch.git-1a82d13f33ac.your-ad-here.call-01559732716-ext-6629@work.hours

Fixes: 2f4df0017baed ("tracing: Add -mcount-nop option support")
Signed-off-by: Vasily Gorbik &lt;gor@linux.ibm.com&gt;
Signed-off-by: Steven Rostedt (VMware) &lt;rostedt@goodmis.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>tracing: Fix out-of-range read in trace_stack_print()</title>
<updated>2019-06-14T20:28:42+00:00</updated>
<author>
<name>Eiichi Tsukata</name>
<email>devel@etsukata.com</email>
</author>
<published>2019-06-10T04:00:16+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=becf33f694dc50656766e0fde8883437d5c8d4b4'/>
<id>becf33f694dc50656766e0fde8883437d5c8d4b4</id>
<content type='text'>
Puts range check before dereferencing the pointer.

Reproducer:

  # echo stacktrace &gt; trace_options
  # echo 1 &gt; events/enable
  # cat trace &gt; /dev/null

KASAN report:

  ==================================================================
  BUG: KASAN: use-after-free in trace_stack_print+0x26b/0x2c0
  Read of size 8 at addr ffff888069d20000 by task cat/1953

  CPU: 0 PID: 1953 Comm: cat Not tainted 5.2.0-rc3+ #5
  Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.12.0-2.fc30 04/01/2014
  Call Trace:
   dump_stack+0x8a/0xce
   print_address_description+0x60/0x224
   ? trace_stack_print+0x26b/0x2c0
   ? trace_stack_print+0x26b/0x2c0
   __kasan_report.cold+0x1a/0x3e
   ? trace_stack_print+0x26b/0x2c0
   kasan_report+0xe/0x20
   trace_stack_print+0x26b/0x2c0
   print_trace_line+0x6ea/0x14d0
   ? tracing_buffers_read+0x700/0x700
   ? trace_find_next_entry_inc+0x158/0x1d0
   s_show+0xea/0x310
   seq_read+0xaa7/0x10e0
   ? seq_escape+0x230/0x230
   __vfs_read+0x7c/0x100
   vfs_read+0x16c/0x3a0
   ksys_read+0x121/0x240
   ? kernel_write+0x110/0x110
   ? perf_trace_sys_enter+0x8a0/0x8a0
   ? syscall_slow_exit_work+0xa9/0x410
   do_syscall_64+0xb7/0x390
   ? prepare_exit_to_usermode+0x165/0x200
   entry_SYSCALL_64_after_hwframe+0x44/0xa9
  RIP: 0033:0x7f867681f910
  Code: b6 fe ff ff 48 8d 3d 0f be 08 00 48 83 ec 08 e8 06 db 01 00 66 0f 1f 44 00 00 83 3d f9 2d 2c 00 00 75 10 b8 00 00 00 00 04
  RSP: 002b:00007ffdabf23488 EFLAGS: 00000246 ORIG_RAX: 0000000000000000
  RAX: ffffffffffffffda RBX: 0000000000020000 RCX: 00007f867681f910
  RDX: 0000000000020000 RSI: 00007f8676cde000 RDI: 0000000000000003
  RBP: 00007f8676cde000 R08: ffffffffffffffff R09: 0000000000000000
  R10: 0000000000000871 R11: 0000000000000246 R12: 00007f8676cde000
  R13: 0000000000000003 R14: 0000000000020000 R15: 0000000000000ec0

  Allocated by task 1214:
   save_stack+0x1b/0x80
   __kasan_kmalloc.constprop.0+0xc2/0xd0
   kmem_cache_alloc+0xaf/0x1a0
   getname_flags+0xd2/0x5b0
   do_sys_open+0x277/0x5a0
   do_syscall_64+0xb7/0x390
   entry_SYSCALL_64_after_hwframe+0x44/0xa9

  Freed by task 1214:
   save_stack+0x1b/0x80
   __kasan_slab_free+0x12c/0x170
   kmem_cache_free+0x8a/0x1c0
   putname+0xe1/0x120
   do_sys_open+0x2c5/0x5a0
   do_syscall_64+0xb7/0x390
   entry_SYSCALL_64_after_hwframe+0x44/0xa9

  The buggy address belongs to the object at ffff888069d20000
   which belongs to the cache names_cache of size 4096
  The buggy address is located 0 bytes inside of
   4096-byte region [ffff888069d20000, ffff888069d21000)
  The buggy address belongs to the page:
  page:ffffea0001a74800 refcount:1 mapcount:0 mapping:ffff88806ccd1380 index:0x0 compound_mapcount: 0
  flags: 0x100000000010200(slab|head)
  raw: 0100000000010200 dead000000000100 dead000000000200 ffff88806ccd1380
  raw: 0000000000000000 0000000000070007 00000001ffffffff 0000000000000000
  page dumped because: kasan: bad access detected

  Memory state around the buggy address:
   ffff888069d1ff00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
   ffff888069d1ff80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  &gt;ffff888069d20000: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                     ^
   ffff888069d20080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
   ffff888069d20100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
  ==================================================================

Link: http://lkml.kernel.org/r/20190610040016.5598-1-devel@etsukata.com

Fixes: 4285f2fcef80 ("tracing: Remove the ULONG_MAX stack trace hackery")
Signed-off-by: Eiichi Tsukata &lt;devel@etsukata.com&gt;
Signed-off-by: Steven Rostedt (VMware) &lt;rostedt@goodmis.org&gt;
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Puts range check before dereferencing the pointer.

Reproducer:

  # echo stacktrace &gt; trace_options
  # echo 1 &gt; events/enable
  # cat trace &gt; /dev/null

KASAN report:

  ==================================================================
  BUG: KASAN: use-after-free in trace_stack_print+0x26b/0x2c0
  Read of size 8 at addr ffff888069d20000 by task cat/1953

  CPU: 0 PID: 1953 Comm: cat Not tainted 5.2.0-rc3+ #5
  Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.12.0-2.fc30 04/01/2014
  Call Trace:
   dump_stack+0x8a/0xce
   print_address_description+0x60/0x224
   ? trace_stack_print+0x26b/0x2c0
   ? trace_stack_print+0x26b/0x2c0
   __kasan_report.cold+0x1a/0x3e
   ? trace_stack_print+0x26b/0x2c0
   kasan_report+0xe/0x20
   trace_stack_print+0x26b/0x2c0
   print_trace_line+0x6ea/0x14d0
   ? tracing_buffers_read+0x700/0x700
   ? trace_find_next_entry_inc+0x158/0x1d0
   s_show+0xea/0x310
   seq_read+0xaa7/0x10e0
   ? seq_escape+0x230/0x230
   __vfs_read+0x7c/0x100
   vfs_read+0x16c/0x3a0
   ksys_read+0x121/0x240
   ? kernel_write+0x110/0x110
   ? perf_trace_sys_enter+0x8a0/0x8a0
   ? syscall_slow_exit_work+0xa9/0x410
   do_syscall_64+0xb7/0x390
   ? prepare_exit_to_usermode+0x165/0x200
   entry_SYSCALL_64_after_hwframe+0x44/0xa9
  RIP: 0033:0x7f867681f910
  Code: b6 fe ff ff 48 8d 3d 0f be 08 00 48 83 ec 08 e8 06 db 01 00 66 0f 1f 44 00 00 83 3d f9 2d 2c 00 00 75 10 b8 00 00 00 00 04
  RSP: 002b:00007ffdabf23488 EFLAGS: 00000246 ORIG_RAX: 0000000000000000
  RAX: ffffffffffffffda RBX: 0000000000020000 RCX: 00007f867681f910
  RDX: 0000000000020000 RSI: 00007f8676cde000 RDI: 0000000000000003
  RBP: 00007f8676cde000 R08: ffffffffffffffff R09: 0000000000000000
  R10: 0000000000000871 R11: 0000000000000246 R12: 00007f8676cde000
  R13: 0000000000000003 R14: 0000000000020000 R15: 0000000000000ec0

  Allocated by task 1214:
   save_stack+0x1b/0x80
   __kasan_kmalloc.constprop.0+0xc2/0xd0
   kmem_cache_alloc+0xaf/0x1a0
   getname_flags+0xd2/0x5b0
   do_sys_open+0x277/0x5a0
   do_syscall_64+0xb7/0x390
   entry_SYSCALL_64_after_hwframe+0x44/0xa9

  Freed by task 1214:
   save_stack+0x1b/0x80
   __kasan_slab_free+0x12c/0x170
   kmem_cache_free+0x8a/0x1c0
   putname+0xe1/0x120
   do_sys_open+0x2c5/0x5a0
   do_syscall_64+0xb7/0x390
   entry_SYSCALL_64_after_hwframe+0x44/0xa9

  The buggy address belongs to the object at ffff888069d20000
   which belongs to the cache names_cache of size 4096
  The buggy address is located 0 bytes inside of
   4096-byte region [ffff888069d20000, ffff888069d21000)
  The buggy address belongs to the page:
  page:ffffea0001a74800 refcount:1 mapcount:0 mapping:ffff88806ccd1380 index:0x0 compound_mapcount: 0
  flags: 0x100000000010200(slab|head)
  raw: 0100000000010200 dead000000000100 dead000000000200 ffff88806ccd1380
  raw: 0000000000000000 0000000000070007 00000001ffffffff 0000000000000000
  page dumped because: kasan: bad access detected

  Memory state around the buggy address:
   ffff888069d1ff00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
   ffff888069d1ff80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  &gt;ffff888069d20000: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                     ^
   ffff888069d20080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
   ffff888069d20100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
  ==================================================================

Link: http://lkml.kernel.org/r/20190610040016.5598-1-devel@etsukata.com

Fixes: 4285f2fcef80 ("tracing: Remove the ULONG_MAX stack trace hackery")
Signed-off-by: Eiichi Tsukata &lt;devel@etsukata.com&gt;
Signed-off-by: Steven Rostedt (VMware) &lt;rostedt@goodmis.org&gt;
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