Re: Kernel oops with 6.14 when enabling TLS

[Hannes Reinecke <hare@suse.com>]

On 3/3/25 12:06, Hannes Reinecke wrote:
> On 3/3/25 08:48, Hannes Reinecke wrote:
>> On 2/28/25 11:47, Hannes Reinecke wrote:
>>> Hi Sagi,
>>>
>>> enabling TLS on latest linus tree reliably crashes my system:
>>>
>>> [  487.018058] ------------[ cut here ]------------
>>> [  487.024046] WARNING: CPU: 9 PID: 6159 at mm/slub.c:4719 
>>> free_large_kmalloc+0x15/0xa0
> [ .. ]
>>>
>>> Haven't found a culprit for that one for now, started bisecting.
>>> Just wanted to report that as a heads-up, maybe you have some idea.
>>>
>>
>> bisect is pointing to
>> 9aec2fb0fd5e ("slab: allocate frozen pages")
>> and, indeed, reverting this patch on top of linus current resolves
>> the issue.
>>
>> Sorry Matthew.
>>
> It's getting even worse; after reverting above patch I'm getting a crash
> here:
> [  968.315152] Oops: general protection fault, probably for non- 
> canonical address 0xdead000000000120: 0000 [#1] PREE
> MPT SMP NOPTI
> [  968.328747] CPU: 30 UID: 0 PID: 665 Comm: kcompactd5 Kdump: loaded 
> Tainted: G        W   E      6.14.0-rc4-defaul
> t+ #306 9ca11b70f9498982db3664c8471cfe00b0a16485
> [  968.345747] Tainted: [W]=WARN, [E]=UNSIGNED_MODULE
> [  968.351913] Hardware name: Lenovo ThinkSystem SR655V3/SB27B09914, 
> BIOS KAE111E-2.10 04/11/2023
> [  968.362371] RIP: 0010:isolate_movable_page+0x7c/0x130
> [  968.368826] Code: 02 75 3c f0 48 0f ba 2b 00 72 34 48 89 df e8 8b e0 
> f6 ff 84 c0 74 20 48 8b 03 a9 00 00 01 00 75
>   16 48 8b 43 18 89 ee 48 89 df <48> 8b 40 fe ff d0 0f 1f 00 84 c0 75 61 
> 48 89 df e8 ff d8 f2 ff f0
> [  968.390698] RSP: 0018:ff582840034c7bd0 EFLAGS: 00010246
> [  968.397354] RAX: dead000000000122 RBX: ffc1af3dcf400000 RCX: 
> ffc1af3dcf400034
> [  968.406145] RDX: dead000000000101 RSI: 000000000000000c RDI: 
> ffc1af3dcf400000
> [  968.414950] RBP: 000000000000000c R08: 0000000000000000 R09: 
> 000000000f400000
> [  968.423755] R10: 0000000000000400 R11: ff4187a00d995780 R12: 
> 00000000003d0000
> [  968.432562] R13: ff582840034c7d30 R14: 0000000000000001 R15: 
> 0000000000000001
> [  968.441365] FS:  0000000000000000(0000) GS:ff41879ffaa00000(0000) 
> knlGS:0000000000000000
> [  968.451245] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> [  968.458488] CR2: 000055b303833c20 CR3: 000000005a838002 CR4: 
> 0000000000771ef0
> [  968.467295] PKRU: 55555554
> [  968.471120] Call Trace:
> [  968.474655]  <TASK>
> [  968.477804]  ? __die_body+0x1a/0x60
> [  968.482521]  ? die_addr+0x38/0x60
> [  968.487030]  ? exc_general_protection+0x19e/0x430
> [  968.493115]  ? asm_exc_general_protection+0x22/0x30
> [  968.499395]  ? isolate_movable_page+0x7c/0x130
> [  968.505180]  isolate_migratepages_block+0x39a/0x1090
> [  968.511555]  ? srso_alias_return_thunk+0x5/0xfbef5
> [  968.517728]  ? update_curr+0x19e/0x220
> [  968.522725]  compact_zone+0x368/0x1090
> [  968.527722]  ? srso_alias_return_thunk+0x5/0xfbef5
> [  968.533896]  compact_node+0xa8/0x120
> [  968.538720]  kcompactd+0x21e/0x2b0
> 
> which again points straight into the 'allocate and free frozen pages'
> patchset. Something's buggered there, and I'm not sure if further
> bisecting will be getting us anywhere.
> 
And now it's even happening without TLS enabled. So seems that
reverting the patch is not sufficient.

Some guidance would be good.

Cheers,

Hannes
-- 
Dr. Hannes Reinecke                  Kernel Storage Architect
hare@suse.com                               +49 911 74053 688
SUSE Software Solutions GmbH, Frankenstr. 146, 90461 Nürnberg
HRB 36809 (AG Nürnberg), GF: I. Totev, A. McDonald, W. Knoblich