Re: [PATCH 4.9 00/41] 4.9.260-rc1 review

[Florian Fainelli]

On 3/5/21 4:22 AM, Greg Kroah-Hartman wrote:
> Ben Hutchings <ben@xxxxxxxxxxxxxxx>
>     futex: Futex_unlock_pi() determinism
> 

Hi Ben,

This particular commit above eventually triggered the following warning
below, this was not caught in my initial testing of the v4.9.260 kernel,
when I gave my Tested-by tag. This appears to be easily reproducible
upon initialization of one of the modules being loaded for that test.

Are there additional changes that we are missing in linux-4.9.y with
respect to futex code?

[  233.128367] ------------[ cut here ]------------
[  233.133104] WARNING: CPU: 3 PID: 1845 at kernel/futex.c:1584
do_futex+0x800/0x974
[  233.140707] Modules linked in: wakeup_drv(O) nexus(PO) brcmv3d(O)
[  233.146950]
[  233.148511] CPU: 3 PID: 1845 Comm: nx_sched_idle_s Tainted: P
   O    4.9.261-1.22 #1
[  233.157072] Hardware name: BCX972180SV (DT)
[  233.161326] task: ffffffc075e12e00 task.stack: ffffffc073110000
[  233.167328] PC is at do_futex+0x800/0x974
[  233.171410] LR is at do_futex+0x784/0x974
[  233.175490] pc : [<ffffff800810f468>] lr : [<ffffff800810f3ec>]
pstate: 600001c5
[  233.183003] sp : ffffffc073113d10
[  233.186380] x29: ffffffc073113d10 x28: 0000000000000000
[  233.191800] x27: 0000000000000735 x26: ffffffc073113df8
[  233.197220] x25: ffffffc07401bc90 x24: 0000000080000735
[  233.202638] x23: ffffffc073110000 x22: 0000000000000000
[  233.208055] x21: 000000000c0cd220 x20: ffffffc07401bc80
[  233.213472] x19: 0000000000000001 x18: 0000000000000000
[  233.218890] x17: 0000007f82b8dfe8 x16: ffffff800810f5dc
[  233.224309] x15: 00000b1a97b40980 x14: 0033240a01207260
[  233.229727] x13: 00000000604b3cb0 x12: 0000000000000018
[  233.235144] x11: 000000000636eae9 x10: 00000000000000e9
[  233.240562] x9 : 003b9aca00000000 x8 : 0000000000000062
[  233.245979] x7 : 0000000000014e26 x6 : 0000000000000000
[  233.251396] x5 : ffffffc07401bcb8 x4 : 0000000000000000
[  233.256814] x3 : 0000000000000001 x2 : 0000000000000000
[  233.262230] x1 : 0000000000000000 x0 : ffffff8008cdf7dd
[  233.267644]
[  233.269192] ---[ end trace 18db5bc47ae34623 ]---
[  233.273877] Call trace:
[  233.276389] Exception stack(0xffffffc073113b10 to 0xffffffc073113c40)
[  233.282913] 3b00:                                   0000000000000001
0000007fffffffff
[  233.290873] 3b20: ffffffc073113d10 ffffff800810f468 00000000600001c5
000000000000003d
[  233.298833] 3b40: ffffffc07401bc90 ffffffc073113df8 000000000c0cd220
0000000000000735
[  233.306791] 3b60: ffffffc073113bd0 ffffff800810e004 0000000000000000
ffffffc073113cd0
[  233.314751] 3b80: 000000000c0cd220 ffffffc073110000 0000000000000000
ffffffc073113cd0
[  233.322711] 3ba0: 0000000000000000 ffffffc076b65bc0 ffffffc073113bd0
ffffff800810e1a4
[  233.330670] 3bc0: 0000000000000000 00000000000409ff ffffffc073113d10
00000000000409ff
[  233.338628] 3be0: ffffff8008cdf7dd 0000000000000000 0000000000000000
0000000000000001
[  233.346586] 3c00: 0000000000000000 ffffffc07401bcb8 0000000000000000
0000000000014e26
[  233.354545] 3c20: 0000000000000062 003b9aca00000000 00000000000000e9
000000000636eae9
[  233.362506] [<ffffff800810f468>] do_futex+0x800/0x974
[  233.367638] [<ffffff800810f738>] SyS_futex+0x15c/0x184
[  233.372861] [<ffffff8008083180>] el0_svc_naked+0x34/0x38
-- 
Florian