* "alloc_tag was not set" when running mm/ksft_hmm.sh
@ 2026-05-06 15:42 Zenghui Yu
2026-05-08 11:53 ` David Hildenbrand (Arm)
0 siblings, 1 reply; 3+ messages in thread
From: Zenghui Yu @ 2026-05-06 15:42 UTC (permalink / raw)
To: linux-mm, linux-kernel
Cc: jgg, leon, Andrew Morton, david, ljs, liam, vbabka, rppt, surenb,
mhocko
Hi all,
Running mm/ksft_hmm.sh triggers the following splat:
------------[ cut here ]------------
alloc_tag was not set
WARNING: ./include/linux/alloc_tag.h:164 at ___free_pages+0x2a0/0x2d0,
CPU#5: hmm-tests/2020
Modules linked in: test_hmm rfkill drm backlight fuse
CPU: 5 UID: 0 PID: 2020 Comm: hmm-tests Kdump: loaded Not tainted
7.1.0-rc2-00099-gadc1e5c6203c-dirty #285 PREEMPT
Hardware name: QEMU QEMU Virtual Machine, BIOS
edk2-stable202408-prebuilt.qemu.org 08/13/2024
pstate: 61400005 (nZCv daif +PAN -UAO -TCO +DIT -SSBS BTYPE=--)
pc : ___free_pages+0x2a0/0x2d0
lr : ___free_pages+0x2a0/0x2d0
sp : ffff80008345b530
x29: ffff80008345b530 x28: ffff80008345b700 x27: ffffffffbfff8040
x26: ffff0000c41cb360 x25: ffff0000c0c64008 x24: ffff800081aae400
x23: 05ffff0000000200 x22: 0000000000000000 x21: 0000000000000000
x20: fffffdffc5f20040 x19: 0000000000000000 x18: fffffffffffe7c78
x17: 0000000000000000 x16: 0000000000000000 x15: fffffffffffe7c98
x14: 00000000000001d1 x13: ffff8000818f3d58 x12: 0000000000000573
x11: fffffffffffe7c98 x10: ffff80008194bd58 x9 : 3ffffffffffff000
x8 : ffff8000818f3d58 x7 : ffff80008194bd58 x6 : 0000000000000000
x5 : ffff0001fedb1088 x4 : 0000000000000001 x3 : 0000000000000000
x2 : 0000000000000000 x1 : 0000000000000000 x0 : ffff0000c7f58000
Call trace:
___free_pages+0x2a0/0x2d0 (P)
__free_pages+0x14/0x20
dmirror_devmem_free+0x13c/0x158 [test_hmm]
free_zone_device_folio+0x144/0x1e4
__folio_put+0x124/0x130
free_folio_and_swap_cache+0xa8/0xcc
__folio_split+0x664/0x7fc
split_folio_to_list+0x50/0x5c
migrate_vma_split_folio+0x13c/0x25c
migrate_vma_collect_pmd+0xed4/0xf68
walk_pgd_range+0x598/0x9a0
__walk_page_range+0x90/0x1a0
walk_page_range_mm_unsafe+0x194/0x20c
walk_page_range+0x20/0x2c
migrate_vma_setup+0x18c/0x224
dmirror_devmem_fault+0x188/0x2b8 [test_hmm]
do_swap_page+0x1458/0x185c
__handle_mm_fault+0x85c/0x1ba0
handle_mm_fault+0xb0/0x290
do_page_fault+0x1f8/0x6f8
do_translation_fault+0x60/0x6c
do_mem_abort+0x44/0x94
el0_da+0x30/0xdc
el0t_64_sync_handler+0xd0/0xe4
el0t_64_sync+0x198/0x19c
---[ end trace 0000000000000000 ]---
lib/test_hmm.c:705 module test_hmm func:dmirror_devmem_alloc_page has
16744448 allocated at module unload
It was tested on kernel built with arm64's virt.config and
+CONFIG_ZONE_DEVICE=y
+CONFIG_DEVICE_PRIVATE=y
+CONFIG_TEST_HMM=m
+CONFIG_MEM_ALLOC_PROFILING=y
+CONFIG_MEM_ALLOC_PROFILING_DEBUG=y
Thanks,
Zenghui
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: "alloc_tag was not set" when running mm/ksft_hmm.sh
2026-05-06 15:42 "alloc_tag was not set" when running mm/ksft_hmm.sh Zenghui Yu
@ 2026-05-08 11:53 ` David Hildenbrand (Arm)
2026-05-08 16:35 ` Alistair Popple
0 siblings, 1 reply; 3+ messages in thread
From: David Hildenbrand (Arm) @ 2026-05-08 11:53 UTC (permalink / raw)
To: Zenghui Yu, linux-mm, linux-kernel
Cc: jgg, leon, Andrew Morton, ljs, liam, vbabka, rppt, surenb, mhocko,
Alistair Popple
On 5/6/26 17:42, Zenghui Yu wrote:
> Hi all,
>
> Running mm/ksft_hmm.sh triggers the following splat:
>
> ------------[ cut here ]------------
> alloc_tag was not set
> WARNING: ./include/linux/alloc_tag.h:164 at ___free_pages+0x2a0/0x2d0,
> CPU#5: hmm-tests/2020
> Modules linked in: test_hmm rfkill drm backlight fuse
> CPU: 5 UID: 0 PID: 2020 Comm: hmm-tests Kdump: loaded Not tainted
> 7.1.0-rc2-00099-gadc1e5c6203c-dirty #285 PREEMPT
> Hardware name: QEMU QEMU Virtual Machine, BIOS
> edk2-stable202408-prebuilt.qemu.org 08/13/2024
> pstate: 61400005 (nZCv daif +PAN -UAO -TCO +DIT -SSBS BTYPE=--)
> pc : ___free_pages+0x2a0/0x2d0
> lr : ___free_pages+0x2a0/0x2d0
> sp : ffff80008345b530
> x29: ffff80008345b530 x28: ffff80008345b700 x27: ffffffffbfff8040
> x26: ffff0000c41cb360 x25: ffff0000c0c64008 x24: ffff800081aae400
> x23: 05ffff0000000200 x22: 0000000000000000 x21: 0000000000000000
> x20: fffffdffc5f20040 x19: 0000000000000000 x18: fffffffffffe7c78
> x17: 0000000000000000 x16: 0000000000000000 x15: fffffffffffe7c98
> x14: 00000000000001d1 x13: ffff8000818f3d58 x12: 0000000000000573
> x11: fffffffffffe7c98 x10: ffff80008194bd58 x9 : 3ffffffffffff000
> x8 : ffff8000818f3d58 x7 : ffff80008194bd58 x6 : 0000000000000000
> x5 : ffff0001fedb1088 x4 : 0000000000000001 x3 : 0000000000000000
> x2 : 0000000000000000 x1 : 0000000000000000 x0 : ffff0000c7f58000
> Call trace:
> ___free_pages+0x2a0/0x2d0 (P)
> __free_pages+0x14/0x20
> dmirror_devmem_free+0x13c/0x158 [test_hmm]
> free_zone_device_folio+0x144/0x1e4
> __folio_put+0x124/0x130
> free_folio_and_swap_cache+0xa8/0xcc
> __folio_split+0x664/0x7fc
> split_folio_to_list+0x50/0x5c
> migrate_vma_split_folio+0x13c/0x25c
> migrate_vma_collect_pmd+0xed4/0xf68
> walk_pgd_range+0x598/0x9a0
> __walk_page_range+0x90/0x1a0
> walk_page_range_mm_unsafe+0x194/0x20c
> walk_page_range+0x20/0x2c
> migrate_vma_setup+0x18c/0x224
> dmirror_devmem_fault+0x188/0x2b8 [test_hmm]
> do_swap_page+0x1458/0x185c
> __handle_mm_fault+0x85c/0x1ba0
> handle_mm_fault+0xb0/0x290
> do_page_fault+0x1f8/0x6f8
> do_translation_fault+0x60/0x6c
> do_mem_abort+0x44/0x94
> el0_da+0x30/0xdc
> el0t_64_sync_handler+0xd0/0xe4
> el0t_64_sync+0x198/0x19c
> ---[ end trace 0000000000000000 ]---
> lib/test_hmm.c:705 module test_hmm func:dmirror_devmem_alloc_page has
> 16744448 allocated at module unload
>
>
> It was tested on kernel built with arm64's virt.config and
>
> +CONFIG_ZONE_DEVICE=y
> +CONFIG_DEVICE_PRIVATE=y
> +CONFIG_TEST_HMM=m
> +CONFIG_MEM_ALLOC_PROFILING=y
> +CONFIG_MEM_ALLOC_PROFILING_DEBUG=y
I assume there is a weird interaction between alloc tags and simulated
ZONE_DEVICE memory in test_hmm.c
@Alistair, any idea?
--
Cheers,
David
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: "alloc_tag was not set" when running mm/ksft_hmm.sh
2026-05-08 11:53 ` David Hildenbrand (Arm)
@ 2026-05-08 16:35 ` Alistair Popple
0 siblings, 0 replies; 3+ messages in thread
From: Alistair Popple @ 2026-05-08 16:35 UTC (permalink / raw)
To: David Hildenbrand (Arm)
Cc: Zenghui Yu, linux-mm, linux-kernel, jgg, leon, Andrew Morton, ljs,
liam, vbabka, rppt, surenb, mhocko
On 2026-05-08 at 21:53 +1000, "David Hildenbrand (Arm)" <david@kernel.org> wrote...
> On 5/6/26 17:42, Zenghui Yu wrote:
> > Hi all,
> >
> > Running mm/ksft_hmm.sh triggers the following splat:
> >
> > ------------[ cut here ]------------
> > alloc_tag was not set
> > WARNING: ./include/linux/alloc_tag.h:164 at ___free_pages+0x2a0/0x2d0,
> > CPU#5: hmm-tests/2020
> > Modules linked in: test_hmm rfkill drm backlight fuse
> > CPU: 5 UID: 0 PID: 2020 Comm: hmm-tests Kdump: loaded Not tainted
> > 7.1.0-rc2-00099-gadc1e5c6203c-dirty #285 PREEMPT
> > Hardware name: QEMU QEMU Virtual Machine, BIOS
> > edk2-stable202408-prebuilt.qemu.org 08/13/2024
> > pstate: 61400005 (nZCv daif +PAN -UAO -TCO +DIT -SSBS BTYPE=--)
> > pc : ___free_pages+0x2a0/0x2d0
> > lr : ___free_pages+0x2a0/0x2d0
> > sp : ffff80008345b530
> > x29: ffff80008345b530 x28: ffff80008345b700 x27: ffffffffbfff8040
> > x26: ffff0000c41cb360 x25: ffff0000c0c64008 x24: ffff800081aae400
> > x23: 05ffff0000000200 x22: 0000000000000000 x21: 0000000000000000
> > x20: fffffdffc5f20040 x19: 0000000000000000 x18: fffffffffffe7c78
> > x17: 0000000000000000 x16: 0000000000000000 x15: fffffffffffe7c98
> > x14: 00000000000001d1 x13: ffff8000818f3d58 x12: 0000000000000573
> > x11: fffffffffffe7c98 x10: ffff80008194bd58 x9 : 3ffffffffffff000
> > x8 : ffff8000818f3d58 x7 : ffff80008194bd58 x6 : 0000000000000000
> > x5 : ffff0001fedb1088 x4 : 0000000000000001 x3 : 0000000000000000
> > x2 : 0000000000000000 x1 : 0000000000000000 x0 : ffff0000c7f58000
> > Call trace:
> > ___free_pages+0x2a0/0x2d0 (P)
> > __free_pages+0x14/0x20
> > dmirror_devmem_free+0x13c/0x158 [test_hmm]
> > free_zone_device_folio+0x144/0x1e4
> > __folio_put+0x124/0x130
> > free_folio_and_swap_cache+0xa8/0xcc
> > __folio_split+0x664/0x7fc
> > split_folio_to_list+0x50/0x5c
> > migrate_vma_split_folio+0x13c/0x25c
> > migrate_vma_collect_pmd+0xed4/0xf68
> > walk_pgd_range+0x598/0x9a0
> > __walk_page_range+0x90/0x1a0
> > walk_page_range_mm_unsafe+0x194/0x20c
> > walk_page_range+0x20/0x2c
> > migrate_vma_setup+0x18c/0x224
> > dmirror_devmem_fault+0x188/0x2b8 [test_hmm]
> > do_swap_page+0x1458/0x185c
> > __handle_mm_fault+0x85c/0x1ba0
> > handle_mm_fault+0xb0/0x290
> > do_page_fault+0x1f8/0x6f8
> > do_translation_fault+0x60/0x6c
> > do_mem_abort+0x44/0x94
> > el0_da+0x30/0xdc
> > el0t_64_sync_handler+0xd0/0xe4
> > el0t_64_sync+0x198/0x19c
> > ---[ end trace 0000000000000000 ]---
> > lib/test_hmm.c:705 module test_hmm func:dmirror_devmem_alloc_page has
> > 16744448 allocated at module unload
> >
> >
> > It was tested on kernel built with arm64's virt.config and
> >
> > +CONFIG_ZONE_DEVICE=y
> > +CONFIG_DEVICE_PRIVATE=y
> > +CONFIG_TEST_HMM=m
> > +CONFIG_MEM_ALLOC_PROFILING=y
> > +CONFIG_MEM_ALLOC_PROFILING_DEBUG=y
>
> I assume there is a weird interaction between alloc tags and simulated
> ZONE_DEVICE memory in test_hmm.c
>
> @Alistair, any idea?
I haven't managed to reproduce this but could imagine that would be the problem
- not sure page_ext is supported for ZONE_DEVICE PRIVATE pages.
I'm still travelling back from LSFMM so will take a closer look next week.
Thanks!
- Alistair
> --
> Cheers,
>
> David
^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2026-05-08 16:36 UTC | newest]
Thread overview: 3+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2026-05-06 15:42 "alloc_tag was not set" when running mm/ksft_hmm.sh Zenghui Yu
2026-05-08 11:53 ` David Hildenbrand (Arm)
2026-05-08 16:35 ` Alistair Popple
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox