Re: [PATCH] lttng-modules: Check the pid_ns before using it because it may be NULL

[Jonathan Rajotte-Julien <jonathan.rajotte-julien@efficios.com>]

Hi,

We released patch level release for our stable branch [1].

These release includes the fix proposed here.

Please validate that it fixes your issues.

[1] https://lists.linuxfoundation.org/pipermail/diamon-discuss/2020-February/000196.html

Cheers

----- Original Message -----
> From: "Li Zhou" <li.zhou@windriver.com>
> To: "Jonathan Rajotte-Julien" <jonathan.rajotte-julien@efficios.com>
> Cc: "openembedded-core" <openembedded-core@lists.openembedded.org>
> Sent: Tuesday, February 25, 2020 3:41:58 AM
> Subject: Re: [OE-core] [PATCH] lttng-modules: Check the pid_ns before using it because it may be NULL

> On 2/20/20 10:47 PM, Jonathan Rajotte-Julien wrote:
>> Hi,
>>
>> Can we get more info on the kernel version and config?
>>
>> Did you submit this on our mailing list?(lttng-dev). If not I would highly
>> recommend that you do so in the future so we can eliminate *custom* patches and
>> get to the bottom of the issue at hand so that the whole community benefit from
>> it.
> 
> 
> Hi, Jonathan:
> 
>         Thank you for you help and suggestion on this. This issue is
> seen on linux 4.18 + lttng-modules 2.10.
> 
> 
>>
>> Cheers
>>
>> ----- Li Zhou <li.zhou@windriver.com> wrote:
>>> Check the pid_ns before using it because it may be NULL to fix below
>>> issue:
>>> <1>[ 22.637196] Unable to handle kernel NULL pointer dereference at
>>> virtual address 0000000000000080
>>> <1>[ 22.645982] Mem abort info:
>>> <1>[ 22.648769] ESR = 0x96000007
>>> <1>[ 22.651817] Exception class = DABT (current EL), IL = 32 bits
>>> <1>[ 22.657730] SET = 0, FnV = 0
>>> <1>[ 22.660777] EA = 0, S1PTW = 0
>>> <1>[ 22.663910] Data abort info:
>>> <1>[ 22.666784] ISV = 0, ISS = 0x00000007
>>> <1>[ 22.670611] CM = 0, WnR = 0
>>> <1>[ 22.673574] user pgtable: 4k pages, 39-bit VAs, pgdp =
>>> 0000000012378f78
>>> <1>[ 22.680180] [0000000000000080] pgd=000000007f023003,
>>> pud=000000007f023003, pmd=000000007f01f003, pte=0000000000000000
>>> <0>[ 22.690794] Internal error: Oops: 96000007 [#1] PREEMPT SMP
>>> <4>[ 22.690797] Modules linked in: adkNetD ncp
>>> lttng_ring_buffer_client_overwrite(C)
>>> lttng_ring_buffer_metadata_client(C) lttng_ring_buffer_client_discard(C)
>>> lttng_ring_buffer_client_mmap_overwrite(C)
>>> lttng_ring_buffer_client_mmap_discard(C)
>>> lttng_ring_buffer_metadata_mmap_client(C) lttng_probe_signal(C)
>>> lttng_probe_printk(C) lttng_probe_sched(C) lttng_probe_irq(C)
>>> lttng_tracer(C) lttng_statedump(C) lttng_ftrace(C)
>>> lttng_lib_ring_buffer(C) lttng_clock_plugin_arm_cntpct(C) lttng_clock(C)
>>> <0>[ 22.690823] Process lttng-sessiond (pid: 3093, stack limit =
>>> 0x000000005d27910f)
>>> <4>[ 22.690828] CPU: 1 PID: 3093 Comm: lttng-sessiond Tainted: G C
>>> 4.18.37-rt820-custom #1
>>> <4>[ 22.690830] Hardware name: DUS33 (CPM2-20) (DT)
>>> <4>[ 22.690833] pstate: 60000005 (nZCv daif -PAN -UAO)
>>> <4>[ 22.690845] pc : do_lttng_statedump+0xcc/0x8a8 [lttng_statedump]
>>> <4>[ 22.690849] lr : do_lttng_statedump+0xc4/0x8a8 [lttng_statedump]
>>> <4>[ 22.690851] sp : ffffffc07fe57ad0
>>> <4>[ 22.690852] x29: ffffffc07fe57ad0 x28: ffffffc008ae2700
>>> <4>[ 22.690856] x27: ffffff8000724000 x26: 0000000000000001
>>> <4>[ 22.690859] x25: ffffff80089c9620 x24: 0000000000000000
>>> <4>[ 22.690862] x23: ffffffc008ae2e10 x22: ffffff80089d3380
>>> <4>[ 22.690865] x21: ffffffc07f450000 x20: ffffffc008ae2700
>>> <4>[ 22.690869] x19: 0000000000000007 x18: 00000000fffffffe
>>> <4>[ 22.690871] x17: 0000000000000000 x16: ffffff800824b980
>>> <4>[ 22.690874] x15: 0000000000000000 x14: 736162203b656e6f
>>> <4>[ 22.690877] x13: 6e203d20676e6964 x12: 0000000000000000
>>> <4>[ 22.690880] x11: 0101010101010101 x10: 7f7f7f7f7f7f7f7f
>>> <4>[ 22.690882] x9 : 3c1f647968721eff x8 : ffffffc0877504c8
>>> <4>[ 22.690886] x7 : 09093a7c093a7c08 x6 : ffffff8010c4b317
>>> <4>[ 22.690888] x5 : 0000000000000000 x4 : 00000040a7575000
>>> <4>[ 22.690891] x3 : ffffffc008ae2e28 x2 : 0000000000000000
>>> <4>[ 22.690894] x1 : 0000000000000000 x0 : 0000000000000000
>>> <4>[ 22.690896] Call trace:
>>> <4>[ 22.690902] do_lttng_statedump+0xcc/0x8a8 [lttng_statedump]
>>> <4>[ 22.690905] lttng_statedump_start+0x20/0x30 [lttng_statedump]
>>> <4>[ 22.690981] lttng_session_enable+0xf0/0x120 [lttng_tracer]
>>> <4>[ 22.691018] lttng_session_ioctl+0x22c/0x328 [lttng_tracer]
>>> <4>[ 22.691026] compat_sys_ioctl+0x110/0x778
>>>
>>> Signed-off-by: Li Zhou <li.zhou@windriver.com>
>>> ---
>>>   ...es-Check-the-pid_ns-before-using-it-becau.patch | 86 ++++++++++++++++++++++
>>>   meta/recipes-kernel/lttng/lttng-modules_2.11.1.bb  |  2 +
>>>   2 files changed, 88 insertions(+)
>>>   create mode 100644
>>>   meta/recipes-kernel/lttng/lttng-modules/0001-lttng-modules-Check-the-pid_ns-before-using-it-becau.patch
>>>
>>> diff --git
>>> a/meta/recipes-kernel/lttng/lttng-modules/0001-lttng-modules-Check-the-pid_ns-before-using-it-becau.patch
>>> b/meta/recipes-kernel/lttng/lttng-modules/0001-lttng-modules-Check-the-pid_ns-before-using-it-becau.patch
>>> new file mode 100644
>>> index 0000000..5306c79
>>> --- /dev/null
>>> +++
>>> b/meta/recipes-kernel/lttng/lttng-modules/0001-lttng-modules-Check-the-pid_ns-before-using-it-becau.patch
>>> @@ -0,0 +1,86 @@
>>> +From 0c0072e005ce9d591518d1819a39264859132561 Mon Sep 17 00:00:00 2001
>>> +From: Li Zhou <li.zhou@windriver.com>
>>> +Date: Wed, 19 Feb 2020 11:14:38 +0800
>>> +Subject: [PATCH] lttng-modules: Check the pid_ns before using it because it
>>> + may be NULL
>>> +
>>> +<1>[ 22.637196] Unable to handle kernel NULL pointer dereference at
>>> +virtual address 0000000000000080
>>> +<1>[ 22.645982] Mem abort info:
>>> +<1>[ 22.648769] ESR = 0x96000007
>>> +<1>[ 22.651817] Exception class = DABT (current EL), IL = 32 bits
>>> +<1>[ 22.657730] SET = 0, FnV = 0
>>> +<1>[ 22.660777] EA = 0, S1PTW = 0
>>> +<1>[ 22.663910] Data abort info:
>>> +<1>[ 22.666784] ISV = 0, ISS = 0x00000007
>>> +<1>[ 22.670611] CM = 0, WnR = 0
>>> +<1>[ 22.673574] user pgtable: 4k pages, 39-bit VAs, pgdp =
>>> +0000000012378f78
>>> +<1>[ 22.680180] [0000000000000080] pgd=000000007f023003,
>>> +pud=000000007f023003, pmd=000000007f01f003, pte=0000000000000000
>>> +<0>[ 22.690794] Internal error: Oops: 96000007 [#1] PREEMPT SMP
>>> +<4>[ 22.690797] Modules linked in: adkNetD ncp
>>> +lttng_ring_buffer_client_overwrite(C)
>>> +lttng_ring_buffer_metadata_client(C) lttng_ring_buffer_client_discard(C)
>>> +lttng_ring_buffer_client_mmap_overwrite(C)
>>> +lttng_ring_buffer_client_mmap_discard(C)
>>> +lttng_ring_buffer_metadata_mmap_client(C) lttng_probe_signal(C)
>>> +lttng_probe_printk(C) lttng_probe_sched(C) lttng_probe_irq(C)
>>> +lttng_tracer(C) lttng_statedump(C) lttng_ftrace(C)
>>> +lttng_lib_ring_buffer(C) lttng_clock_plugin_arm_cntpct(C) lttng_clock(C)
>>> +<0>[ 22.690823] Process lttng-sessiond (pid: 3093, stack limit =
>>> +0x000000005d27910f)
>>> +<4>[ 22.690828] CPU: 1 PID: 3093 Comm: lttng-sessiond Tainted: G C
>>> +4.18.37-rt820-custom #1
>>> +<4>[ 22.690830] Hardware name: DUS33 (CPM2-20) (DT)
>>> +<4>[ 22.690833] pstate: 60000005 (nZCv daif -PAN -UAO)
>>> +<4>[ 22.690845] pc : do_lttng_statedump+0xcc/0x8a8 [lttng_statedump]
>>> +<4>[ 22.690849] lr : do_lttng_statedump+0xc4/0x8a8 [lttng_statedump]
>>> +<4>[ 22.690851] sp : ffffffc07fe57ad0
>>> +<4>[ 22.690852] x29: ffffffc07fe57ad0 x28: ffffffc008ae2700
>>> +<4>[ 22.690856] x27: ffffff8000724000 x26: 0000000000000001
>>> +<4>[ 22.690859] x25: ffffff80089c9620 x24: 0000000000000000
>>> +<4>[ 22.690862] x23: ffffffc008ae2e10 x22: ffffff80089d3380
>>> +<4>[ 22.690865] x21: ffffffc07f450000 x20: ffffffc008ae2700
>>> +<4>[ 22.690869] x19: 0000000000000007 x18: 00000000fffffffe
>>> +<4>[ 22.690871] x17: 0000000000000000 x16: ffffff800824b980
>>> +<4>[ 22.690874] x15: 0000000000000000 x14: 736162203b656e6f
>>> +<4>[ 22.690877] x13: 6e203d20676e6964 x12: 0000000000000000
>>> +<4>[ 22.690880] x11: 0101010101010101 x10: 7f7f7f7f7f7f7f7f
>>> +<4>[ 22.690882] x9 : 3c1f647968721eff x8 : ffffffc0877504c8
>>> +<4>[ 22.690886] x7 : 09093a7c093a7c08 x6 : ffffff8010c4b317
>>> +<4>[ 22.690888] x5 : 0000000000000000 x4 : 00000040a7575000
>>> +<4>[ 22.690891] x3 : ffffffc008ae2e28 x2 : 0000000000000000
>>> +<4>[ 22.690894] x1 : 0000000000000000 x0 : 0000000000000000
>>> +<4>[ 22.690896] Call trace:
>>> +<4>[ 22.690902] do_lttng_statedump+0xcc/0x8a8 [lttng_statedump]
>>> +<4>[ 22.690905] lttng_statedump_start+0x20/0x30 [lttng_statedump]
>>> +<4>[ 22.690981] lttng_session_enable+0xf0/0x120 [lttng_tracer]
>>> +<4>[ 22.691018] lttng_session_ioctl+0x22c/0x328 [lttng_tracer]
>>> +<4>[ 22.691026] compat_sys_ioctl+0x110/0x778
>>> +
>>> +Signed-off-by: Liguang Li <liguang.li@windriver.com>
>>> +
>>> +Upstream-Status: Pending
>>> +
>>> +Signed-off-by: Li Zhou <li.zhou@windriver.com>
>>> +---
>>> + lttng-statedump-impl.c | 2 +-
>>> + 1 file changed, 1 insertion(+), 1 deletion(-)
>>> +
>>> +diff --git a/lttng-statedump-impl.c b/lttng-statedump-impl.c
>>> +index 1c09e51..fb609e3 100644
>>> +--- a/lttng-statedump-impl.c
>>> ++++ b/lttng-statedump-impl.c
>>> +@@ -397,7 +397,7 @@ void lttng_statedump_process_ns(struct lttng_session
>>> *session,
>>> + 	do {
>>> + 		trace_lttng_statedump_process_state(session,
>>> + 			p, type, mode, submode, status, pid_ns);
>>> +-		pid_ns = pid_ns->parent;
>>> ++		pid_ns = pid_ns ? pid_ns->parent : NULL;
>>> + 	} while (pid_ns);
>>> + }
>>> +
>>> +--
>>> +1.9.1
>>> +
>>> diff --git a/meta/recipes-kernel/lttng/lttng-modules_2.11.1.bb
>>> b/meta/recipes-kernel/lttng/lttng-modules_2.11.1.bb
>>> index c833ff7..cbd43e3 100644
>>> --- a/meta/recipes-kernel/lttng/lttng-modules_2.11.1.bb
>>> +++ b/meta/recipes-kernel/lttng/lttng-modules_2.11.1.bb
>>> @@ -11,6 +11,7 @@ COMPATIBLE_HOST =
>>> '(x86_64|i.86|powerpc|aarch64|mips|nios2|arm|riscv).*-linux'
>>>   SRC_URI = "https://lttng.org/files/${BPN}/${BPN}-${PV}.tar.bz2 \
>>>              file://Makefile-Do-not-fail-if-CONFIG_TRACEPOINTS-is-not-en.patch \
>>>              file://BUILD_RUNTIME_BUG_ON-vs-gcc7.patch \
>>> +
>>> file://0001-lttng-modules-Check-the-pid_ns-before-using-it-becau.patch
>>> \
>>>              "
>>>   
>>>   SRC_URI[md5sum] = "0d964723c8765b39835e5e6efc60a604"
>>> @@ -36,6 +37,7 @@ DEFAULT_PREFERENCE_class-devupstream = "-1"
>>>   SRC_URI_class-devupstream =
>>>   "git://git.lttng.org/lttng-modules;branch=stable-2.11 \
>>>              file://Makefile-Do-not-fail-if-CONFIG_TRACEPOINTS-is-not-en.patch \
>>>              file://BUILD_RUNTIME_BUG_ON-vs-gcc7.patch \
>>> +
>>> file://0001-lttng-modules-Check-the-pid_ns-before-using-it-becau.patch
>>> \
>>>              "
>>>   SRCREV_class-devupstream = "6ad0e68b43c3e52fcb3d47c4d823a7b84aeb443a"
>>>   PV_class-devupstream = "2.11.1+git${SRCPV}"
>>> --
>>> 1.9.1
>>>
>>> --
>>> _______________________________________________
>>> Openembedded-core mailing list
>>> Openembedded-core@lists.openembedded.org
>>> http://lists.openembedded.org/mailman/listinfo/openembedded-core
>>
> --
> Best Regards!
> Zhou Li
> Phone number: 86-10-84778511