Bug 200055
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Description
Erhard F.
2018-06-13 00:50:01 UTC
Created attachment 276511 [details]
4.17.1 kernel config
Same bug on my other G5 11,2 (64bit kernel, 64bit userland). Created attachment 277113 [details]
dmesg.txt (G5 11,2)
Created attachment 277115 [details]
4.17.3 kernel config
Created attachment 277287 [details]
4.18-rc3 kernel config
Created attachment 277289 [details]
dmesg.txt (G5 7,3 + kernel 4.18-rc3)
Created attachment 278857 [details]
dmesg.txt (G5 11,2 + kernel 4.19-rc5)
Some info from a 4.19-rc5 debug kernel.
Created attachment 278859 [details]
4.19-rc5 kernel config
Created attachment 279423 [details]
dmesg.txt (G4 3,6 + kernel 4.19.1)
Same issue on a G4 MDD, 32bit kernel.
Created attachment 280471 [details]
dmesg.txt (G5 7,3 + kernel 5.0.0-rc2)
Still here on 5.0.0-rc2.
What happens if you do:
diff --git a/arch/powerpc/platforms/powermac/low_i2c.c b/arch/powerpc/platforms/powermac/low_i2c.c
index 4de058a20d2b..b8bbc4b0f8f6 100644
--- a/arch/powerpc/platforms/powermac/low_i2c.c
+++ b/arch/powerpc/platforms/powermac/low_i2c.c
@@ -586,7 +586,6 @@ static void __init kw_i2c_add(struct pmac_i2c_host_kw *host,
bus->close = kw_i2c_close;
bus->xfer = kw_i2c_xfer;
mutex_init(&bus->mutex);
- lockdep_set_class(&bus->mutex, &bus->lock_key);
if (controller == busnode)
bus->flags = pmac_i2c_multibus;
list_add(&bus->link, &pmac_i2c_busses);
Created attachment 280503 [details]
dmesg.txt (G5 7,3 + kernel 5.0.0-rc2 + patch)
I saved this as a .diff but the patch did not apply on 5.0.0-rc2:
/usr/src/linux # patch -p1 < ../low_i2c.diff
patching file arch/powerpc/platforms/powermac/low_i2c.c
Hunk #1 FAILED at 586.
1 out of 1 hunk FAILED -- saving rejects to file arch/powerpc/platforms/powermac/low_i2c.c.rej
However I deleted the relevant line manually in arch/powerpc/platforms/powermac/low_i2c.c and rebuilt the kernel. The change is that now there are less "BUG: key c00000027e01f730 not in .data!" messages and more i2c adresses are detected. But it still gets triggered.
Created attachment 281899 [details]
dmesg.txt (G5 7,3 + kernel 5.1.0-rc1)
The bug persists, but output changed a bit since 5.0.x.
5.0.2-gentoo: BUG: key c00000027e01ef30 not in .data!
5.1.0-rc1: BUG: key c00000027e01ef20 has not been registered!
Also on 5.0.2 there are several "BUG: key c00000027e01ef30 not in .data!" messages, but in 5.1.0-rc1 only the 1st one.
Created attachment 281901 [details]
5.1.0-rc1 kernel config (G5 7,3)
Created attachment 283675 [details]
dmesg.txt (G5 11,2 + kernel 4.9.184)
By running some older kernels from the stable series I noticed that 4.4.x and 4.9.x are not affected by this lockdep issue. First stable series it shows up is 4.14.x.
I am rather curious what a bisect will throw up when I have time to do it. ;)
Created attachment 283677 [details]
dmesg.txt (G5 11,2 + kernel 4.14.132)
Created attachment 283679 [details]
4.9.184 kernel .config (G5 11,2)
Created attachment 283681 [details]
4.14.132 kernel .config (G5 11,2)
Created attachment 284001 [details] bisect.log At last... I got the offending commit. Funnily enough it is about silencing lockdep warnings. ;) 9e607f72748ddc5620aeeb8d1f32f30c79b360b9 is the first bad commit commit 9e607f72748ddc5620aeeb8d1f32f30c79b360b9 Author: Denis Kirjanov <kda@linux-powerpc.org> Date: Wed Sep 21 14:34:58 2016 +0300 i2c_powermac: shut up lockdep warning That's unclear why lockdep shows the following warning but adding a lockdep class to struct pmac_i2c_bus solves it [ 20.507795] ====================================================== [ 20.507796] [ INFO: possible circular locking dependency detected ] [ 20.507800] 4.8.0-rc7-00037-gd2ffb01 #21 Not tainted [ 20.507801] ------------------------------------------------------- [ 20.507803] swapper/0/1 is trying to acquire lock: [ 20.507818] (&bus->mutex){+.+.+.}, at: [<c000000000052830>] .pmac_i2c_open+0x30/0x100 [ 20.507819] [ 20.507819] but task is already holding lock: [ 20.507829] (&policy->rwsem){+.+.+.}, at: [<c00000000068adcc>] .cpufreq_online+0x1ac/0x9d0 [ 20.507830] [ 20.507830] which lock already depends on the new lock. [ 20.507830] [ 20.507832] [ 20.507832] the existing dependency chain (in reverse order) is: [ 20.507837] [ 20.507837] -> #4 (&policy->rwsem){+.+.+.}: [ 20.507844] [<c00000000082385c>] .down_write+0x6c/0x110 [ 20.507849] [<c00000000068adcc>] .cpufreq_online+0x1ac/0x9d0 [ 20.507855] [<c0000000004d76d8>] .subsys_interface_register+0xb8/0x110 [ 20.507860] [<c000000000689bb0>] .cpufreq_register_driver+0x1d0/0x250 [ 20.507866] [<c000000000b4f8f4>] .g5_cpufreq_init+0x9cc/0xa28 [ 20.507872] [<c00000000000a98c>] .do_one_initcall+0x5c/0x1d0 [ 20.507878] [<c000000000b0f86c>] .kernel_init_freeable+0x1ac/0x28c [ 20.507883] [<c00000000000b3bc>] .kernel_init+0x1c/0x140 [ 20.507887] [<c0000000000098f4>] .ret_from_kernel_thread+0x58/0x64 [ 20.507894] [ 20.507894] -> #3 (subsys mutex#2){+.+.+.}: [ 20.507899] [<c000000000820448>] .mutex_lock_nested+0xa8/0x590 [ 20.507903] [<c0000000004d7f24>] .bus_probe_device+0x44/0xe0 [ 20.507907] [<c0000000004d5208>] .device_add+0x508/0x730 [ 20.507911] [<c0000000004dd528>] .register_cpu+0x118/0x190 [ 20.507916] [<c000000000b14450>] .topology_init+0x148/0x248 [ 20.507921] [<c00000000000a98c>] .do_one_initcall+0x5c/0x1d0 [ 20.507925] [<c000000000b0f86c>] .kernel_init_freeable+0x1ac/0x28c [ 20.507929] [<c00000000000b3bc>] .kernel_init+0x1c/0x140 [ 20.507934] [<c0000000000098f4>] .ret_from_kernel_thread+0x58/0x64 [ 20.507939] [ 20.507939] -> #2 (cpu_add_remove_lock){+.+.+.}: [ 20.507944] [<c000000000820448>] .mutex_lock_nested+0xa8/0x590 [ 20.507950] [<c000000000087a9c>] .register_cpu_notifier+0x2c/0x70 [ 20.507955] [<c000000000b267e0>] .spawn_ksoftirqd+0x18/0x4c [ 20.507959] [<c00000000000a98c>] .do_one_initcall+0x5c/0x1d0 [ 20.507964] [<c000000000b0f770>] .kernel_init_freeable+0xb0/0x28c [ 20.507968] [<c00000000000b3bc>] .kernel_init+0x1c/0x140 [ 20.507972] [<c0000000000098f4>] .ret_from_kernel_thread+0x58/0x64 [ 20.507978] [ 20.507978] -> #1 (&host->mutex){+.+.+.}: [ 20.507982] [<c000000000820448>] .mutex_lock_nested+0xa8/0x590 [ 20.507987] [<c0000000000527e8>] .kw_i2c_open+0x18/0x30 [ 20.507991] [<c000000000052894>] .pmac_i2c_open+0x94/0x100 [ 20.507995] [<c000000000b220a0>] .smp_core99_probe+0x260/0x410 [ 20.507999] [<c000000000b185bc>] .smp_prepare_cpus+0x280/0x2ac [ 20.508003] [<c000000000b0f748>] .kernel_init_freeable+0x88/0x28c [ 20.508008] [<c00000000000b3bc>] .kernel_init+0x1c/0x140 [ 20.508012] [<c0000000000098f4>] .ret_from_kernel_thread+0x58/0x64 [ 20.508018] [ 20.508018] -> #0 (&bus->mutex){+.+.+.}: [ 20.508023] [<c0000000000ed5b4>] .lock_acquire+0x84/0x100 [ 20.508027] [<c000000000820448>] .mutex_lock_nested+0xa8/0x590 [ 20.508032] [<c000000000052830>] .pmac_i2c_open+0x30/0x100 [ 20.508037] [<c000000000052e14>] .pmac_i2c_do_begin+0x34/0x120 [ 20.508040] [<c000000000056bc0>] .pmf_call_one+0x50/0xd0 [ 20.508045] [<c00000000068ff1c>] .g5_pfunc_switch_volt+0x2c/0xc0 [ 20.508050] [<c00000000068fecc>] .g5_pfunc_switch_freq+0x1cc/0x1f0 [ 20.508054] [<c00000000068fc2c>] .g5_cpufreq_target+0x2c/0x40 [ 20.508058] [<c0000000006873ec>] .__cpufreq_driver_target+0x23c/0x840 [ 20.508062] [<c00000000068c798>] .cpufreq_gov_performance_limits+0x18/0x30 [ 20.508067] [<c00000000068915c>] .cpufreq_start_governor+0xac/0x100 [ 20.508071] [<c00000000068a788>] .cpufreq_set_policy+0x208/0x260 [ 20.508076] [<c00000000068abdc>] .cpufreq_init_policy+0x6c/0xb0 [ 20.508081] [<c00000000068ae70>] .cpufreq_online+0x250/0x9d0 [ 20.508085] [<c0000000004d76d8>] .subsys_interface_register+0xb8/0x110 [ 20.508090] [<c000000000689bb0>] .cpufreq_register_driver+0x1d0/0x250 [ 20.508094] [<c000000000b4f8f4>] .g5_cpufreq_init+0x9cc/0xa28 [ 20.508099] [<c00000000000a98c>] .do_one_initcall+0x5c/0x1d0 [ 20.508103] [<c000000000b0f86c>] .kernel_init_freeable+0x1ac/0x28c [ 20.508107] [<c00000000000b3bc>] .kernel_init+0x1c/0x140 [ 20.508112] [<c0000000000098f4>] .ret_from_kernel_thread+0x58/0x64 [ 20.508113] [ 20.508113] other info that might help us debug this: [ 20.508113] [ 20.508121] Chain exists of: [ 20.508121] &bus->mutex --> subsys mutex#2 --> &policy->rwsem [ 20.508121] [ 20.508123] Possible unsafe locking scenario: [ 20.508123] [ 20.508124] CPU0 CPU1 [ 20.508125] ---- ---- [ 20.508128] lock(&policy->rwsem); [ 20.508132] lock(subsys mutex#2); [ 20.508135] lock(&policy->rwsem); [ 20.508138] lock(&bus->mutex); [ 20.508139] [ 20.508139] *** DEADLOCK *** [ 20.508139] [ 20.508141] 3 locks held by swapper/0/1: [ 20.508150] #0: (cpu_hotplug.lock){++++++}, at: [<c000000000087838>] .get_online_cpus+0x48/0xc0 [ 20.508159] #1: (subsys mutex#2){+.+.+.}, at: [<c0000000004d7670>] .subsys_interface_register+0x50/0x110 [ 20.508168] #2: (&policy->rwsem){+.+.+.}, at: [<c00000000068adcc>] .cpufreq_online+0x1ac/0x9d0 [ 20.508169] [ 20.508169] stack backtrace: [ 20.508173] CPU: 0 PID: 1 Comm: swapper/0 Not tainted 4.8.0-rc7-00037-gd2ffb01 #21 [ 20.508175] Call Trace: [ 20.508180] [c0000000790c2b90] [c00000000082cc70] .dump_stack+0xe0/0x14c (unreliable) [ 20.508184] [c0000000790c2c20] [c000000000828c88] .print_circular_bug+0x350/0x388 [ 20.508188] [c0000000790c2cd0] [c0000000000ecb0c] .__lock_acquire+0x196c/0x1d30 [ 20.508192] [c0000000790c2e50] [c0000000000ed5b4] .lock_acquire+0x84/0x100 [ 20.508196] [c0000000790c2f20] [c000000000820448] .mutex_lock_nested+0xa8/0x590 [ 20.508201] [c0000000790c3030] [c000000000052830] .pmac_i2c_open+0x30/0x100 [ 20.508206] [c0000000790c30c0] [c000000000052e14] .pmac_i2c_do_begin+0x34/0x120 [ 20.508209] [c0000000790c3150] [c000000000056bc0] .pmf_call_one+0x50/0xd0 [ 20.508213] [c0000000790c31e0] [c00000000068ff1c] .g5_pfunc_switch_volt+0x2c/0xc0 [ 20.508217] [c0000000790c3250] [c00000000068fecc] .g5_pfunc_switch_freq+0x1cc/0x1f0 [ 20.508221] [c0000000790c3320] [c00000000068fc2c] .g5_cpufreq_target+0x2c/0x40 [ 20.508226] [c0000000790c3390] [c0000000006873ec] .__cpufreq_driver_target+0x23c/0x840 [ 20.508230] [c0000000790c3440] [c00000000068c798] .cpufreq_gov_performance_limits+0x18/0x30 [ 20.508235] [c0000000790c34b0] [c00000000068915c] .cpufreq_start_governor+0xac/0x100 [ 20.508239] [c0000000790c3530] [c00000000068a788] .cpufreq_set_policy+0x208/0x260 [ 20.508244] [c0000000790c35d0] [c00000000068abdc] .cpufreq_init_policy+0x6c/0xb0 [ 20.508249] [c0000000790c3940] [c00000000068ae70] .cpufreq_online+0x250/0x9d0 [ 20.508253] [c0000000790c3a30] [c0000000004d76d8] .subsys_interface_register+0xb8/0x110 [ 20.508258] [c0000000790c3ad0] [c000000000689bb0] .cpufreq_register_driver+0x1d0/0x250 [ 20.508262] [c0000000790c3b60] [c000000000b4f8f4] .g5_cpufreq_init+0x9cc/0xa28 [ 20.508267] [c0000000790c3c20] [c00000000000a98c] .do_one_initcall+0x5c/0x1d0 [ 20.508271] [c0000000790c3d00] [c000000000b0f86c] .kernel_init_freeable+0x1ac/0x28c [ 20.508276] [c0000000790c3db0] [c00000000000b3bc] .kernel_init+0x1c/0x140 [ 20.508280] [c0000000790c3e30] [c0000000000098f4] .ret_from_kernel_thread+0x58/0x64 Signed-off-by: Denis Kirjanov <kda@linux-powerpc.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> :040000 040000 18ec5f23dbd03c624aae71f3cbb05466dd38bf91 d4d7866e7cf3060e9ae1c76ad390194d4d789dcd M arch Created attachment 284003 [details]
4.9.0-rc5+ kernel .config (G5 11,2, final bisect)
Created attachment 284005 [details]
dmesg.txt (G5 11,2 + kernel 4.9.0-rc5+, final bisect)
Created attachment 294375 [details]
dmesg (kernel 5.11-rc1, G5 11,2)
Still in 5.11-rc1.
Created attachment 294377 [details]
kernel .config (kernel 5.11-rc1, G5 11,2)
Created attachment 300558 [details]
kernel .config (kernel 5.17-rc7, PowerMac G5 11,2)
Created attachment 300559 [details]
dmesg (kernel 5.17-rc7, PowerMac G5 11,2)
Have not seen this for some time. Current v5.17-rc7 and stable kernels are fine, so closing. |