Segmentation Fault in iwd with ell 0.68 Due to l_netlink_send()

Segmentation Fault in iwd with ell 0.68 Due to l_netlink_send()

[Rajdeep Malakar]

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Hi,

I’m encountering a segmentation fault in iwd after upgrading the ell 
library from version 0.67 to 0.68. The issue seems to be related to the 
l_netlink_send() function in the ell library.

Issue Details:

- Function Causing Segfault: l_netlink_send()
- Error: SIGSEGV (Segmentation Fault)
- Library Path: /usr/lib/libell.so.0
- System: Arch Linux x86-64

Reproduction Steps:

1. Upgrade ell from version 0.67 to 0.68.
2. Start iwd.
3. Observe the segmentation fault.

I confirmed this issue using gdb, which indicates that l_netlink_send() 
in the ell library is causing the segmentation fault.

Reverting to ell version 0.67 resolves the issue without causing a 
segmentation fault.

Since there have been no updates or commits in the repository since the 
release, I wanted to bring this to your attention. This might be a 
specific problem with the recent version, and any insights or solutions 
would be greatly appreciated.

Please let me know if additional information is needed or if there are 
any known issues with this version.

---
regards,
rajdeep

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Re: Segmentation Fault in iwd with ell 0.68 Due to l_netlink_send()

[Denis Kenzior]

Hi Rajdeep,

On 8/26/24 1:14 PM, Rajdeep Malakar wrote:
> Hi,
> 
> I’m encountering a segmentation fault in iwd after upgrading the ell library 
> from version 0.67 to 0.68. The issue seems to be related to the l_netlink_send() 
> function in the ell library.

Thanks for the report.  Do you have a backtrace you can share by any chance?

Regards,
-Denis

Re: Segmentation Fault in iwd with ell 0.68 Due to l_netlink_send()

[Rajdeep Malakar]

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Hi Denis,

On 27/08/24 00:16, Denis Kenzior wrote:
> Hi Rajdeep,
> 
> On 8/26/24 1:14 PM, Rajdeep Malakar wrote:
>> Hi,
>>
>> I’m encountering a segmentation fault in iwd after upgrading the ell 
>> library from version 0.67 to 0.68. The issue seems to be related to 
>> the l_netlink_send() function in the ell library.
> 
> Thanks for the report.  Do you have a backtrace you can share by any 
> chance?
> 
> Regards,
> -Deni
Unfortunately, the `libell.so` I have (from Arch's [extra-testing] repo) 
wasn't compiled with debuginfo, so all the backtrace I have is:

#0  0x00007ffff7f22de6 in l_netlink_send () from /usr/lib/libell.so.0
#1  0x000055555556d53d in ?? ()
#2  0x00005555555ae380 in ?? ()
#3  0x00007ffff7f25b95 in ?? () from /usr/lib/libell.so.0
#4  0x00007ffff7f203cb in ?? () from /usr/lib/libell.so.0
#5  0x00007ffff7f20655 in l_main_iterate () from /usr/lib/libell.so.0
#6  0x00007ffff7f20ace in l_main_run () from /usr/lib/libell.so.0
#7  0x00007ffff7f223a4 in l_main_run_with_signal () from 
/usr/lib/libell.so.0
#8  0x000055555555fd13 in ?? ()
#9  0x00007ffff7d0ee08 in ?? () from /usr/lib/libc.so.6
#10 0x00007ffff7d0eecc in __libc_start_main () from /usr/lib/libc.so.6
#11 0x0000555555560575 in ?? ()

I will try to compile it with debuginfo and get the backtrace.

-- 
regards,
rajdeep


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Re: Segmentation Fault in iwd with ell 0.68 Due to l_netlink_send()

[Rajdeep Malakar]

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On 27/08/24 00:25, Rajdeep Malakar wrote:
Hi Denis,

> Hi Denis,
> 
> On 27/08/24 00:16, Denis Kenzior wrote:
>> Hi Rajdeep,
>>
>> On 8/26/24 1:14 PM, Rajdeep Malakar wrote:
>>> Hi,
>>>
>>> I’m encountering a segmentation fault in iwd after upgrading the ell 
>>> library from version 0.67 to 0.68. The issue seems to be related to 
>>> the l_netlink_send() function in the ell library.
>>
>> Thanks for the report.  Do you have a backtrace you can share by any 
>> chance?
>>
>> Regards,
>> -Deni
> Unfortunately, the `libell.so` I have (from Arch's [extra-testing] repo) 
> wasn't compiled with debuginfo, so all the backtrace I have is:
> 
> #0  0x00007ffff7f22de6 in l_netlink_send () from /usr/lib/libell.so.0
> #1  0x000055555556d53d in ?? ()
> #2  0x00005555555ae380 in ?? ()
> #3  0x00007ffff7f25b95 in ?? () from /usr/lib/libell.so.0
> #4  0x00007ffff7f203cb in ?? () from /usr/lib/libell.so.0
> #5  0x00007ffff7f20655 in l_main_iterate () from /usr/lib/libell.so.0
> #6  0x00007ffff7f20ace in l_main_run () from /usr/lib/libell.so.0
> #7  0x00007ffff7f223a4 in l_main_run_with_signal () from 
> /usr/lib/libell.so.0
> #8  0x000055555555fd13 in ?? ()
> #9  0x00007ffff7d0ee08 in ?? () from /usr/lib/libc.so.6
> #10 0x00007ffff7d0eecc in __libc_start_main () from /usr/lib/libc.so.6
> #11 0x0000555555560575 in ?? ()
> 
> I will try to compile it with debuginfo and get the backtrace.
> 

So, I compiled ell with a bit more info:

Program received signal SIGSEGV, Segmentation fault.
0x00007ffff7f3e17c in l_netlink_send (netlink=0x55555563bc60, 
message=0x12, function=0x0, user_data=0x555555651e50, destroy=0x10) at 
ell/netlink.c:413
413             if (unlikely(message->nest_level))

a bit more backtrace:

#0  0x00007ffff7f3e17c in l_netlink_send (netlink=0x55555563bc60, 
message=0x12, function=0x0, user_data=0x555555651e50, destroy=0x10) at 
ell/netlink.c:413
#1  0x000055555556d53d in ?? ()
#2  0x00005555555ae380 in ?? ()
#3  0x00007ffff7f40014 in process_unicast (genl=<optimized out>, 
nlmsg=0x7fffffffc140) at ell/genl.c:860
#4  received_data (io=<optimized out>, user_data=0x55555563b8b0) at 
ell/genl.c:972
#5  0x00007ffff7f3c2ac in io_callback (fd=<optimized out>, events=1, 
user_data=0x55555563b800) at ell/io.c:105
#6  0x00007ffff7f3b495 in l_main_iterate (timeout=<optimized out>) at 
ell/main.c:461
#7  0x00007ffff7f3b55c in l_main_run () at ell/main.c:508
#8  l_main_run () at ell/main.c:490
#9  0x00007ffff7f3b77b in l_main_run_with_signal (callback=<optimized 
out>, user_data=0x0) at ell/main.c:630
#10 0x000055555555fd13 in ?? ()
#11 0x00007ffff7d0ae08 in ?? () from /usr/lib/libc.so.6
#12 0x00007ffff7d0aecc in __libc_start_main () from /usr/lib/libc.so.6
#13 0x0000555555560575 in ?? ()

Let me know if you need more info.
-- 
regards,
rajdeep


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Re: Segmentation Fault in iwd with ell 0.68 Due to l_netlink_send()

[Denis Kenzior]

Hi Rajdeep,

> 
> So, I compiled ell with a bit more info:
> 
> Program received signal SIGSEGV, Segmentation fault.
> 0x00007ffff7f3e17c in l_netlink_send (netlink=0x55555563bc60, message=0x12, 
> function=0x0, user_data=0x555555651e50, destroy=0x10) at ell/netlink.c:413
> 413             if (unlikely(message->nest_level))
> 
> a bit more backtrace:
> 
> #0  0x00007ffff7f3e17c in l_netlink_send (netlink=0x55555563bc60, message=0x12, 
> function=0x0, user_data=0x555555651e50, destroy=0x10) at ell/netlink.c:413
> #1  0x000055555556d53d in ?? ()
> #2  0x00005555555ae380 in ?? ()
> #3  0x00007ffff7f40014 in process_unicast (genl=<optimized out>, 
> nlmsg=0x7fffffffc140) at ell/genl.c:860
> #4  received_data (io=<optimized out>, user_data=0x55555563b8b0) at ell/genl.c:972
> #5  0x00007ffff7f3c2ac in io_callback (fd=<optimized out>, events=1, 
> user_data=0x55555563b800) at ell/io.c:105
> #6  0x00007ffff7f3b495 in l_main_iterate (timeout=<optimized out>) at 
> ell/main.c:461
> #7  0x00007ffff7f3b55c in l_main_run () at ell/main.c:508
> #8  l_main_run () at ell/main.c:490
> #9  0x00007ffff7f3b77b in l_main_run_with_signal (callback=<optimized out>, 
> user_data=0x0) at ell/main.c:630
> #10 0x000055555555fd13 in ?? ()
> #11 0x00007ffff7d0ae08 in ?? () from /usr/lib/libc.so.6
> #12 0x00007ffff7d0aecc in __libc_start_main () from /usr/lib/libc.so.6
> #13 0x0000555555560575 in ?? ()
> 
> Let me know if you need more info.

I suspect that this is a binary compatibility problem.  ell API is not stable, 
so ell + iwd are released in tandem.  ell 0.68 breaks certain netlink APIs.  iwd 
2.19 requires ell 0.67.  iwd 2.20 will require ell 0.68, etc.

Regards,
-Denis

Re: Segmentation Fault in iwd with ell 0.68 Due to l_netlink_send()

[Rajdeep Malakar]

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Hi Denis,

On 27/08/24 00:50, Denis Kenzior wrote:
> Hi Rajdeep,
> 
>>
>> So, I compiled ell with a bit more info:
>>
>> Program received signal SIGSEGV, Segmentation fault.
>> 0x00007ffff7f3e17c in l_netlink_send (netlink=0x55555563bc60, 
>> message=0x12, function=0x0, user_data=0x555555651e50, destroy=0x10) at 
>> ell/netlink.c:413
>> 413             if (unlikely(message->nest_level))
>>
>> a bit more backtrace:
>>
>> #0  0x00007ffff7f3e17c in l_netlink_send (netlink=0x55555563bc60, 
>> message=0x12, function=0x0, user_data=0x555555651e50, destroy=0x10) at 
>> ell/netlink.c:413
>> #1  0x000055555556d53d in ?? ()
>> #2  0x00005555555ae380 in ?? ()
>> #3  0x00007ffff7f40014 in process_unicast (genl=<optimized out>, 
>> nlmsg=0x7fffffffc140) at ell/genl.c:860
>> #4  received_data (io=<optimized out>, user_data=0x55555563b8b0) at 
>> ell/genl.c:972
>> #5  0x00007ffff7f3c2ac in io_callback (fd=<optimized out>, events=1, 
>> user_data=0x55555563b800) at ell/io.c:105
>> #6  0x00007ffff7f3b495 in l_main_iterate (timeout=<optimized out>) at 
>> ell/main.c:461
>> #7  0x00007ffff7f3b55c in l_main_run () at ell/main.c:508
>> #8  l_main_run () at ell/main.c:490
>> #9  0x00007ffff7f3b77b in l_main_run_with_signal (callback=<optimized 
>> out>, user_data=0x0) at ell/main.c:630
>> #10 0x000055555555fd13 in ?? ()
>> #11 0x00007ffff7d0ae08 in ?? () from /usr/lib/libc.so.6
>> #12 0x00007ffff7d0aecc in __libc_start_main () from /usr/lib/libc.so.6
>> #13 0x0000555555560575 in ?? ()
>>
>> Let me know if you need more info.
> 
> I suspect that this is a binary compatibility problem.  ell API is not 
> stable, so ell + iwd are released in tandem.  ell 0.68 breaks certain 
> netlink APIs.  iwd 2.19 requires ell 0.67.  iwd 2.20 will require ell 
> 0.68, etc.
> 
> Regards,
> -Denis
> 

Thanks for the quick reply. If that's the case, then sorry for bothering 
you.
-- 
regards,
rajdeep


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