Re: INFO: [BISECTED] Regression: A Problem with /sys/kernel/debug/kmemleak output: backtrace not printed since 6.2.0-rc1

[Mirsad Goran Todorovac <mirsad.todorovac@alu.unizg.hr>]

On 17. 01. 2023. 03:03, 黄朝阳 (Zhaoyang Huang) wrote:
>>>>>> /sys/kernel/debug/kmemleak output: backtrace not printed since
>>>>>> 6.2.0-rc1
>>>>>>
>>>>>>
>>>>>>> On 12. 01. 2023. 20:50, Mirsad Todorovac wrote:
>>>>>>>> Hi all,
>>>>>>>>
>>>>>>>> there seems to be a problem with the output of
>>>>>>> /sys/kernel/debug/kmemleak:
>>>>>>>>
>>>>>>>> [root@pc-mtodorov ~]# cat /sys/kernel/debug/kmemleak unreferenced
>>>>>>>> object 0xffff951c118568b0 (size 16):
>>>>>>>>     comm "kworker/u12:2", pid 56, jiffies 4294893952 (age 4356.548s)
>>>>>>>>     hex dump (first 16 bytes):
>>>>>>>>       6d 65 6d 73 74 69 63 6b 30 00 00 00 00 00 00 00 memstick0.......
>>>>>>>>     backtrace:
>>>>>>>> [root@pc-mtodorov ~]#
>>>>>>>>
>>>>>>>> Apparently, backtrace of called functions on the stack is no longer
>>>>>>>> printed
>>>>>>> with the list of memory leaks.
>>>>>>>>
>>>>>>>> This appeared on Lenovo desktop 10TX000VCR, with AlmaLinux 8.7 and
>>>>>>>> BIOS version M22KT49A (11/10/2022) and 6.2-rc1 and 6.2-rc2 builds.
>>>>>>>>
>>>>>>>> This worked on 6.1 with the same CONFIG_KMEMLEAK=y and MGLRU
>>>>>>> enabled
>>>>>>>> on a vanilla mainstream kernel from Mr. Torvalds' tree. I don't
>>>>>>>> know if this is
>>>>>>> deliberate feature for some reason or a bug.
>>>>>>>>
>>>>>>>> Please find attached the config, lshw and kmemleak output.
>>>>>>>>
>>>>>>>> The bisection gave this commit as the culprit for the severed stack
>>>>>>>> backtrace print in /sys/kernel/debug/kmemleak:
>>>>>>>>
>>>>>>>> mtodorov@domac:~/linux/kernel/linux_torvalds$ git bisect good
>>>>>>>> 56a61617dd2276cbc56a6c868599716386d70041 is the first bad commit
>>>>>>>> commit 56a61617dd2276cbc56a6c868599716386d70041
>>>>>>>> Author: Zhaoyang Huang <zhaoyang.huang@unisoc.com>
>>>>>>>> Date:   Thu Oct 27 17:50:24 2022 +0800
>>>>>>>>
>>>>>>>>       mm: use stack_depot for recording kmemleak's backtrace
>>>>>>>>
>>>>>>>>       Using stack_depot to record kmemleak's backtrace which has
>>>> been
>>>>>>>>       implemented on slub for reducing redundant information.
>>>>>>>>
>>>>>>>> The complete bisect log is:
>>>>>>>>
>>>>>>>> mtodorov@domac:~/linux/kernel/linux_torvalds$ git bisect log git
>>>>>>>> bisect start '--' 'mm'
>>>>>>>> # good: [830b3c68c1fb1e9176028d02ef86f3cf76aa2476] Linux 6.1 git
>>>>>>>> bisect good 830b3c68c1fb1e9176028d02ef86f3cf76aa2476
>>>>>>>> # bad: [1b929c02afd37871d5afb9d498426f83432e71c2] Linux 6.2-rc1 git
>>>>>>>> bisect bad 1b929c02afd37871d5afb9d498426f83432e71c2
>>>>>>>> # good: [8b9ed79c2d587bec5f603d66801478a5af9af842] Merge tag
>>>>>>>> 'x86_asm_for_v6.2' of
>>>>>>>> git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
>>>>>>>> git bisect good 8b9ed79c2d587bec5f603d66801478a5af9af842
>>>>>>>> # good: [e83b39d6bbdb6d25bd6f5c258832774635d29b47] mm: make
>>>>>>>> drop_caches keep reclaiming on all nodes git bisect good
>>>>>>>> e83b39d6bbdb6d25bd6f5c258832774635d29b47
>>>>>>>> # good: [9997bc017549acd6425e32300eff28424ffeeb6b] zsmalloc:
>>>>>>> implement
>>>>>>>> writeback mechanism for zsmalloc git bisect good
>>>>>>>> 9997bc017549acd6425e32300eff28424ffeeb6b
>>>>>>>> # good: [6287b7dae80944bfa37784a8f9d6861a4facaa6e] mm,thp,rmap:
>>>> fix
>>>>>>>> races between updates of subpages_mapcount git bisect good
>>>>>>>> 6287b7dae80944bfa37784a8f9d6861a4facaa6e
>>>>>>>> # good: [8fa590bf344816c925810331eea8387627bbeb40] Merge tag
>>>>>>>> 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm
>>>>>>>> git bisect good 8fa590bf344816c925810331eea8387627bbeb40
>>>>>>>> # good: [4f292c4de4f6fb83776c0ff22674121eb6ddfa2f] Merge tag
>>>>>>>> 'x86_mm_for_6.2_v2' of
>>>>>>>> git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
>>>>>>>> git bisect good 4f292c4de4f6fb83776c0ff22674121eb6ddfa2f
>>>>>>>> # bad: [1ea9d333ba475041efe43d9d9bc32e64aea2ea2b] Merge tag
>>>>>>>> 'mm-stable-2022-12-17-2' of
>>>>>>>> git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
>>>>>>>> git bisect bad 1ea9d333ba475041efe43d9d9bc32e64aea2ea2b
>>>>>>>> # bad: [56a61617dd2276cbc56a6c868599716386d70041] mm: use
>>>>>>> stack_depot
>>>>>>>> for recording kmemleak's backtrace git bisect bad
>>>>>>>> 56a61617dd2276cbc56a6c868599716386d70041
>>>>>>>> # good: [61b963b52f59524e27692bc1c14bfb2459e32eb3] mm/gup_test:
>>>>>>> free
>>>>>>>> memory allocated via kvcalloc() using kvfree() git bisect good
>>>>>>>> 61b963b52f59524e27692bc1c14bfb2459e32eb3
>>>>>>>> # first bad commit: [56a61617dd2276cbc56a6c868599716386d70041]
>>>> mm:
>>>>>>> use
>>>>>>>> stack_depot for recording kmemleak's backtrace # good:
>>>>>>>> [9102b78b6f6ae6af3557114c265c266b312c1319] maple_tree: update
>>>>>>>> copyright dates for test code git bisect good
>>>>>>>> 9102b78b6f6ae6af3557114c265c266b312c1319
>>>>>>>> # first bad commit: [56a61617dd2276cbc56a6c868599716386d70041]
>>>> mm:
>>>>>>> use
>>>>>>>> stack_depot for recording kmemleak's backtrace You have mail in
>>>>>>>> /var/mail/mtodorov mtodorov@domac:~/linux/kernel/linux_torvalds$
>>>>>>>>
>>>>>>>> The platform is 10TX000VCR
>>>>>>> (LENOVO_MT_10TX_BU_Lenovo_FM_V530S-07ICB)
>>>>>>>> running AlmaLinux 8.7 (CentOS clone) and BIOS M22KT49A.
>>>>>>>>
>>>>>>>> GCC used was:
>>>>>>>>
>>>>>>>> mtodorov@domac:~/linux/kernel/linux_torvalds$ gcc --version gcc
>>>>>>>> (Debian 8.3.0-6) 8.3.0 Copyright (C) 2018 Free Software Foundation,
>>>>>>>> Inc.
>>>>>>>> This is free software; see the source for copying conditions.
>>>>>>>> There is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A
>>>>>>> PARTICULAR PURPOSE.
>>>>>>>> mtodorov@domac:~/linux/kernel/linux_torvalds$
>>>>>>>>
>>>>>>>> Hope this helps.
>>>>>>>>
>>>>>>>> I lack the insight to pinpoint the exact fault in the patch.
>>>>>>>
>>>>>>> P.S.
>>>>>>>
>>>>>>> To further complicate things, on Ubuntu 22.10 Lenovo Ideapad 3
>>>>>>> 15ITL6 laptop the kmemleak stack backtrace is printed correctly with
>>>>>>> the same kernels (but .deb instead of .rpm for the same build):
>>>>>>>
>>>>>>> unreferenced object 0xffff94ca88e042d0 (size 80):
>>>>>>>    comm "thermald", pid 768, jiffies 4294893592 (age 78581.504s)
>>>>>>>    hex dump (first 32 bytes):
>>>>>>>      00 00 00 00 00 00 00 00 0d 01 2d 00 00 00 00 00  ..........-.....
>>>>>>>      af 07 01 80 fd ac ff ff 00 00 00 00 00 00 00 00  ................
>>>>>>>    backtrace:
>>>>>>>      [<ffffffffa0dcb921>] slab_post_alloc_hook+0x91/0x320
>>>>>>>      [<ffffffffa0dcfb79>] kmem_cache_alloc+0x169/0x2f0
>>>>>>>      [<ffffffffa12b1def>] acpi_os_acquire_object+0x2c/0x32
>>>>>>>      [<ffffffffa12b1ea2>] acpi_ps_alloc_op+0x4a/0x99
>>>>>>>      [<ffffffffa12af5c8>] acpi_ps_get_next_arg+0x611/0x761
>>>>>>>      [<ffffffffa12afbbc>] acpi_ps_parse_loop+0x494/0x8d7
>>>>>>>      [<ffffffffa12b1434>] acpi_ps_parse_aml+0x1bb/0x561
>>>>>>>      [<ffffffffa12b24c8>] acpi_ps_execute_method+0x20f/0x2d5
>>>>>>>      [<ffffffffa12a7acf>] acpi_ns_evaluate+0x34d/0x4f3
>>>>>>>      [<ffffffffa12ad6a3>] acpi_evaluate_object+0x180/0x3ae
>>>>>>>      [<ffffffffa1269ca8>] acpi_run_osc+0x128/0x250
>>>>>>>      [<ffffffffc0bbb14f>] int3400_thermal_run_osc+0x6f/0xc0
>>>>>>> [int3400_thermal]
>>>>>>>      [<ffffffffc0bbb293>] current_uuid_store+0xe3/0x120
>>>> [int3400_thermal]
>>>>>>>      [<ffffffffa13b8ed4>] dev_attr_store+0x14/0x30
>>>>>>>      [<ffffffffa0ee0458>] sysfs_kf_write+0x38/0x50
>>>>>>>      [<ffffffffa0edf516>] kernfs_fop_write_iter+0x146/0x1d0 You have
>>>>>>> new mail in /var/mail/root
>>>>>>> root@marvin-IdeaPad-3-15ITL6:/home/marvin#
>>>>>>>
>>>>>>> Regards,
>>>>>>> Mirsad
>>>>>>
>>>>>> thanks for head up. Could you please help to check If
>>>>>> CONFIG_STACKTRACE and CONFIG_STACKDEPOT is enabled on the fault
>>>> kernel?
>>>>> Please try the patch below if the configs are right. I think it should
>>>>> be caused by the late ready for kmemleak
>>>>>
>>>>> commit 556eb1927da99ab366e370d593fc32da946768c3
>>>>> Author: Zhaoyang Huang <zhaoyang.huang@unisoc.com>
>>>>> Date:   Fri Jan 13 14:13:39 2023 +0800
>>>>>
>>>>>       mm: instroduce a flag to indicate stack_depot's ready
>>>>>
>>>>>       try to solve the kmemleak's late ready issue.
>>>>>
>>>>> diff --git a/mm/kmemleak.c b/mm/kmemleak.c index 762b91f..7eb24bc
>>>>> 100644
>>>>> --- a/mm/kmemleak.c
>>>>> +++ b/mm/kmemleak.c
>>>>> @@ -216,6 +216,7 @@ struct kmemleak_object {  static int
>>>> kmemleak_warning;
>>>>>    /* set if a fatal kmemleak error has occurred */  static int
>>>>> kmemleak_error;
>>>>> +static int kmemleak_stadep_initialized;
>>>>>
>>>>>    /* minimum and maximum address that may be valid pointers */  static
>>>> unsigned long min_addr = ULONG_MAX; @@ -601,7 +602,7 @@ static noinline
>>>> depot_stack_handle_t set_track_prepare(void)
>>>>>           unsigned long entries[MAX_TRACE];
>>>>>           unsigned int nr_entries;
>>>>>
>>>>> -       if (!kmemleak_initialized)
>>>>> +       if (!kmemleak_stadep_initialized)
>>>>>                   return 0;
>>>>>           nr_entries = stack_trace_save(entries, ARRAY_SIZE(entries), 3);
>>>>>           trace_handle = stack_depot_save(entries, nr_entries,
>>>> GFP_NOWAIT); @@ -2110,6 +2111,7 @@ void __init kmemleak_init(void)
>>>>>                   create_object((unsigned long)__start_ro_after_init,
>>>>>                                 __end_ro_after_init -
>>>> __start_ro_after_init,
>>>>>                                 KMEMLEAK_GREY, GFP_ATOMIC);
>>>>> +       kmemleak_stadep_initialized = 1;
>>>>>    }
>>>>
>>>> Hi, Zhaoyang,
>>>>
>>>> Sorry, applied the patch and rebuilt, but it didn't work for me:
>>>>
>>>> [root@pc-mtodorov marvin]# uname -rms
>>>> Linux 6.2.0-rc3-mglru-kmemlk-patch-zhaoyang1+ x86_64 [root@pc-mtodorov
>>>> marvin]# cat /sys/kernel/debug/kmemleak [root@pc-mtodorov marvin]# echo
>>>> scan | tee !$ echo scan | tee /sys/kernel/debug/kmemleak scan
>>>> [root@pc-mtodorov marvin]# cat /sys/kernel/debug/kmemleak unreferenced
>>>> object 0xffff98938fed1ee0 (size 16):
>>>>    comm "kworker/u12:2", pid 57, jiffies 4294894053 (age 66.616s)
>>>>    hex dump (first 16 bytes):
>>>>      6d 65 6d 73 74 69 63 6b 30 00 00 00 00 00 00 00  memstick0.......
>>>>    backtrace:
>>>> [root@pc-mtodorov marvin]#
>>>>
>>>> Still the stack backtrace list is severed.
>>>> CONFIG_STACKDEPOT and CONFIG_STACKTRACE are both "=y":
>>>>
>>>> [root@pc-mtodorov marvin]# grep -E 'CONFIG_(STACKTRACE|STACKDEPOT)'
>>>> /boot/config-6.2.0-rc3-mglru-kmemlk-patch-zhaoyang1+
>>>> CONFIG_STACKTRACE_SUPPORT=y
>>>> CONFIG_STACKDEPOT=y
>>>> # CONFIG_STACKTRACE_BUILD_ID is not set
>>>> CONFIG_STACKTRACE=y
>>>> [root@pc-mtodorov marvin]#
>>>>
>>>> Your patch was successfully applied (after some tweaks):
>>>>
>>>> mtodorov@domac:~/linux/kernel/linux_torvalds$ git diff mm diff --git
>>>> a/mm/kmemleak.c b/mm/kmemleak.c index 92f670edbf51..78fd3b89b057
>>>> 100644
>>>> --- a/mm/kmemleak.c
>>>> +++ b/mm/kmemleak.c
>>>> @@ -216,6 +216,7 @@ static int kmemleak_initialized;
>>>>   static int kmemleak_warning;
>>>>   /* set if a fatal kmemleak error has occurred */
>>>>   static int kmemleak_error;
>>>> +static int kmemleak_stadep_initialized;
>>>>
>>>>   /* minimum and maximum address that may be valid pointers */
>>>>   static unsigned long min_addr = ULONG_MAX; @@ -601,7 +602,7 @@ static
>>>> noinline depot_stack_handle_t set_track_prepare(void)
>>>>          unsigned long entries[MAX_TRACE];
>>>>          unsigned int nr_entries;
>>>>
>>>> -       if (!kmemleak_initialized)
>>>> +       if (!kmemleak_stadep_initialized)
>>>>                  return 0;
>>>>          nr_entries = stack_trace_save(entries, ARRAY_SIZE(entries), 3);
>>>>          trace_handle = stack_depot_save(entries, nr_entries,
>>>> GFP_NOWAIT); @@ -2110,6 +2111,7 @@ void __init kmemleak_init(void)
>>>>                  create_object((unsigned long)__start_ro_after_init,
>>>>                                __end_ro_after_init -
>>>> __start_ro_after_init,
>>>>                                KMEMLEAK_GREY, GFP_ATOMIC);
>>>> +       kmemleak_stadep_initialized = 1;
>>>>   }
>>>>
>>>>   /*
>>>> mtodorov@domac:~/linux/kernel/linux_torvalds$
>>>>
>>>> Please verify that the above is correct.
>>> It is correct. Another reason could be the stack is less than 3 layers which could be surpassed by stack_trace_save. Could you please try to modify the code as bellow and try again.
>>> static noinline depot_stack_handle_t set_track_prepare(void)
>>> {
>>>     depot_stack_handle_t trace_handle;
>>>     unsigned long entries[MAX_TRACE];
>>>     unsigned int nr_entries;
>>>
>>>     if (!kmemleak_initialized)
>>>         return 0;
>>> -    nr_entries = stack_trace_save(entries, ARRAY_SIZE(entries), 3);
>>> +    nr_entries = stack_trace_save(entries, ARRAY_SIZE(entries), 0);
>>>     trace_handle = stack_depot_save(entries, nr_entries, GFP_NOWAIT);
>>>
>>>     return trace_handle;
>>> }
>>
>> Tried that, rebuilt, still no luck:
>>
>> [root@pc-mtodorov marvin]# uname -rms
>> Linux 6.2.0-rc3-mglru-kmemlk-patch-zhaoyang2+ x86_64
>> [root@pc-mtodorov marvin]# cat /sys/kernel/debug/kmemleak
>> unreferenced object 0xffff8e8c86483c00 (size 16):
>>   comm "kworker/u12:5", pid 364, jiffies 4294894029 (age 135.024s)
>>   hex dump (first 16 bytes):
>>     6d 65 6d 73 74 69 63 6b 30 00 00 00 00 00 00 00  memstick0.......
>>   backtrace:
>> unreferenced object 0xffff8e8c8edb3f70 (size 16):
>>   comm "kworker/u12:5", pid 364, jiffies 4294894033 (age 135.008s)
>>   hex dump (first 16 bytes):
>>     6d 65 6d 73 74 69 63 6b 30 00 00 00 00 00 00 00  memstick0.......
>>   backtrace:
>> [root@pc-mtodorov marvin]#
>>
>> What I have here is:
>>
>> static noinline depot_stack_handle_t set_track_prepare(void)
>> {
>>         depot_stack_handle_t trace_handle;
>>         unsigned long entries[MAX_TRACE];
>>         unsigned int nr_entries;
>>
>>         if (!kmemleak_stadep_initialized)
>>                 return 0;
>>         nr_entries = stack_trace_save(entries, ARRAY_SIZE(entries), 0);
>>         trace_handle = stack_depot_save(entries, nr_entries, GFP_NOWAIT);
>>
>>         return trace_handle;
>> }
>>
>> Maybe this will help (dmesg says that Stack Depot is disabled due to errors?):
>>
>> [    0.072031] Memory: 16152080K/16658536K available (18432K kernel code, 4118K rwdata, 7184K rodata, 4420K init, 7684K bss, 506196K reserved, 0K cma-reserved)
>> [    0.072219] SLUB: HWalign=64, Order=0-3, MinObjects=0, CPUs=6, Nodes=1
>> [    0.072222] Stack Depot allocating hash table of 1048576 entries with kvcalloc
>> [    0.072226] swapper: vmalloc error: size 8388608, vm_struct allocation failed, mode:0xdc0(GFP_KERNEL|__GFP_ZERO), nodemask=(null),cpuset=(null),mems_allowed=0-1023
>> [    0.072235] CPU: 0 PID: 0 Comm: swapper Not tainted 6.2.0-rc3-mglru-kmemlk-patch-zhaoyang2+ #23
>> [    0.072237] Hardware name: LENOVO 10TX000VCR/3140, BIOS M22KT49A 11/10/2022
>> [    0.072238] Call Trace:
>> [    0.072240]  <TASK>
>> [    0.072242]  dump_stack_lvl+0x49/0x63
>> [    0.072248]  dump_stack+0x10/0x16
>> [    0.072250]  warn_alloc.cold.161+0x75/0xe8
>> [    0.072255]  ? __get_vm_area_node+0x14d/0x160
>> [    0.072260]  __vmalloc_node_range+0x5e5/0x7d0
>> [    0.072264]  ? stack_depot_init.cold.2+0x7e/0xb3
>> [    0.072267]  ? __kmalloc_large_node+0xf8/0x150
>> [    0.072270]  ? kvmalloc_node+0x4f/0xe0
>> [    0.072274]  kvmalloc_node+0xb1/0xe0
>> [    0.072276]  ? stack_depot_init.cold.2+0x7e/0xb3
>> [    0.072278]  stack_depot_init.cold.2+0x7e/0xb3
>> [    0.072280]  kmemleak_init+0x1b/0x114
>> [    0.072284]  start_kernel+0x710/0x9dc
>> [    0.072288]  x86_64_start_reservations+0x24/0x2a
>> [    0.072290]  x86_64_start_kernel+0xf2/0xfd
>> [    0.072292]  secondary_startup_64_no_verify+0xe5/0xeb
>> [    0.072297]  </TASK>
>> [    0.072298] Mem-Info:
>> [    0.072299] active_anon:0 inactive_anon:0 isolated_anon:0
>>                 active_file:0 inactive_file:0 isolated_file:0
>>                 unevictable:0 dirty:0 writeback:0
>>                 slab_reclaimable:0 slab_unreclaimable:26
>>                 mapped:0 shmem:0 pagetables:0
>>                 sec_pagetables:0 bounce:0
>>                 kernel_misc_reclaimable:0
>>                 free:4037994 free_pcp:0 free_cma:0
>> [    0.072303] Node 0 active_anon:0kB inactive_anon:0kB active_file:0kB inactive_file:0kB unevictable:0kB isolated(anon):0kB isolated(file):0kB mapped:0kB dirty:0kB writeback:0kB shmem:0kB shmem_thp: 0kB shmem_pmdmapped: 0kB anon_thp: 0kB writeback_tmp:0kB kernel_stack:0kB pagetables:0kB sec_pagetables:0kB all_unreclaimable? no
>> [    0.072307] Node 0 DMA free:14336kB boost:0kB min:0kB low:0kB high:0kB reserved_highatomic:0KB active_anon:0kB inactive_anon:0kB active_file:0kB inactive_file:0kB unevictable:0kB writepending:0kB present:15992kB managed:14336kB mlocked:0kB bounce:0kB free_pcp:0kB local_pcp:0kB free_cma:0kB
>> [    0.072311] lowmem_reserve[]: 0 0 0 0 0
>> [    0.072314] Node 0 DMA32 free:2085160kB boost:0kB min:0kB low:0kB high:0kB reserved_highatomic:0KB active_anon:0kB inactive_anon:0kB active_file:0kB inactive_file:0kB unevictable:0kB writepending:0kB present:2257392kB managed:2085160kB mlocked:0kB bounce:0kB free_pcp:0kB local_pcp:0kB free_cma:0kB
>> [    0.072318] lowmem_reserve[]: 0 0 0 0 0
>> [    0.072321] Node 0 Normal free:14052480kB boost:0kB min:0kB low:0kB high:0kB reserved_highatomic:0KB active_anon:0kB inactive_anon:0kB active_file:0kB inactive_file:0kB unevictable:0kB writepending:0kB present:14385152kB managed:14052844kB mlocked:0kB bounce:0kB free_pcp:0kB local_pcp:0kB free_cma:0kB
>> [    0.072325] lowmem_reserve[]: 0 0 0 0 0
>> [    0.072328] Node 0 DMA: 0*4kB 0*8kB 0*16kB 0*32kB 0*64kB 0*128kB 0*256kB 0*512kB 2*1024kB (UM) 2*2048kB (M) 2*4096kB (M) = 14336kB
>> [    0.072338] Node 0 DMA32: 8*4kB (M) 9*8kB (M) 8*16kB (M) 8*32kB (M) 7*64kB (M) 7*128kB (M) 8*256kB (M) 7*512kB (M) 5*1024kB (M) 6*2048kB (M) 503*4096kB (M) = 2085160kB
>> [    0.072352] Node 0 Normal: 8*4kB (UM) 8*8kB (M) 2*16kB (UM) 2*32kB (M) 1*64kB (M) 3*128kB (UM) 2*256kB (M) 4*512kB (UM) 2*1024kB (UM) 3*2048kB (UM) 3428*4096kB (M) = 14052480kB
>> [    0.072366] 0 total pagecache pages
>> [    0.072367] 0 pages in swap cache
>> [    0.072367] Free swap  = 0kB
>> [    0.072368] Total swap = 0kB
>> [    0.072369] 4164634 pages RAM
>> [    0.072369] 0 pages HighMem/MovableOnly
>> [    0.072370] 126549 pages reserved
>> [    0.072371] 0 pages hwpoisoned
>> [    0.072372] Stack Depot hash table allocation failed, disabling
> 
> Hi again,
> 
> I have an additional info:
> 
> Here we see Stack Depot trying to alocate 1024 * 1024 entires on a 16 GiB RAM
> AlmaLinux 8.7 (CentOS clone):
> 
> [    0.071875] Stack Depot allocating hash table of 1048576 entries with kvcalloc
> [    0.071879] swapper: vmalloc error: size 8388608, vm_struct allocation failed, mode:0xdc0(GFP_KERNEL|__GFP_ZERO), nodemask=(null),cpuset=(null),mems_allowed=0-1023
> [    0.071888] CPU: 0 PID: 0 Comm: swapper Not tainted 6.2.0-rc3-mglru-kmemlk-nokasan-fixed-rcu+ #2
> [    0.071891] Hardware name: LENOVO 10TX000VCR/3140, BIOS M22KT49A 11/10/2022
> 
> On another machine with just 8 GiB this mechanism is less demanding, requests
> slightly more than 512 * 1024 entries and succeeds:
> 
> [    0.037858] Stack Depot allocating hash table of 524288 entries with kvcalloc
> [    0.038225] ftrace: allocating 52222 entries in 204 pages
> 
> I am not that deep into kernel code to debug this :-(
> 
> As plain kvcalloc() fails, the only thing that comes to mind - maybe 0.072 s
> since boot is still too early to request 8.3 MB? What are the probable causes
> that kvcalloc and vmalloc should fail?
> 
> Thanks,
> Mirsad
> 
> Please help to check if the patch bellow will help. thanks. stack_depot_early_init will get memory directly from memblock_alloc. 
> 
> diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
> index 401ad4b..50cc9f5 100644
> --- a/lib/Kconfig.debug
> +++ b/lib/Kconfig.debug
> @@ -727,6 +727,7 @@ config DEBUG_KMEMLEAK
>         select KALLSYMS
>         select CRC32
>         select STACKDEPOT
> +       select STACKDEPOT_ALWAYS_INIT
>         help
>           Say Y here if you want to enable the memory leak
>           detector. The memory allocation/freeing is traced in a way

Congrats! This worked. I got the /sys/kernel/debug/kmemleak stacktrace back:
[root@pc-mtodorov marvin]# cat /sys/kernel/debug/kmemleak 
unreferenced object 0xffff9543d2402850 (size 16):
  comm "kworker/u12:4", pid 348, jiffies 4294894065 (age 59.252s)
  hex dump (first 16 bytes):
    6d 65 6d 73 74 69 63 6b 30 00 00 00 00 00 00 00  memstick0.......
  backtrace:
    [<ffffffffa7002c9c>] set_track_prepare+0x3c/0x70
    [<ffffffffa700349f>] __create_object+0x11f/0x3a0
    [<ffffffffa7b820ec>] kmemleak_alloc+0x7c/0x90
    [<ffffffffa6fcb9f1>] slab_post_alloc_hook+0x91/0x320
    [<ffffffffa6fd1faf>] __kmem_cache_alloc_node+0x1bf/0x2b0
    [<ffffffffa6f4fbb5>] __kmalloc_node_track_caller+0x55/0x140
    [<ffffffffa6f40b96>] kstrdup+0x36/0x70
    [<ffffffffa6f40c08>] kstrdup_const+0x28/0x30
    [<ffffffffa72fc348>] kvasprintf_const+0x78/0xa0
    [<ffffffffa7a8a903>] kobject_set_name_vargs+0x23/0xa0
    [<ffffffffa75ba2b3>] dev_set_name+0x53/0x70
    [<ffffffffc038ad3f>] memstick_check+0xff/0x384 [memstick]
    [<ffffffffa6cf6054>] process_one_work+0x214/0x3f0
    [<ffffffffa6cf6274>] worker_thread+0x34/0x3d0
    [<ffffffffa6d003cd>] kthread+0xed/0x120
    [<ffffffffa6c039f9>] ret_from_fork+0x29/0x50
unreferenced object 0xffff9543c71ad070 (size 16):
  comm "kworker/u12:4", pid 348, jiffies 4294894071 (age 59.228s)
  hex dump (first 16 bytes):
    6d 65 6d 73 74 69 63 6b 30 00 00 00 00 00 00 00  memstick0.......
  backtrace:
    [<ffffffffa7002c9c>] set_track_prepare+0x3c/0x70
    [<ffffffffa700349f>] __create_object+0x11f/0x3a0
    [<ffffffffa7b820ec>] kmemleak_alloc+0x7c/0x90
    [<ffffffffa6fcb9f1>] slab_post_alloc_hook+0x91/0x320
    [<ffffffffa6fd1faf>] __kmem_cache_alloc_node+0x1bf/0x2b0
    [<ffffffffa6f4fbb5>] __kmalloc_node_track_caller+0x55/0x140
    [<ffffffffa6f40b96>] kstrdup+0x36/0x70
    [<ffffffffa6f40c08>] kstrdup_const+0x28/0x30
    [<ffffffffa72fc348>] kvasprintf_const+0x78/0xa0
    [<ffffffffa7a8a903>] kobject_set_name_vargs+0x23/0xa0
    [<ffffffffa75ba2b3>] dev_set_name+0x53/0x70
    [<ffffffffc038ad3f>] memstick_check+0xff/0x384 [memstick]
    [<ffffffffa6cf6054>] process_one_work+0x214/0x3f0
    [<ffffffffa6cf6274>] worker_thread+0x34/0x3d0
    [<ffffffffa6d003cd>] kthread+0xed/0x120
    [<ffffffffa6c039f9>] ret_from_fork+0x29/0x50
[root@pc-mtodorov marvin]# 

dmesg shows indeed an earlier allocation of the stack depot:

[    0.032827] Kernel command line: BOOT_IMAGE=(hd0,gpt5)/vmlinuz-6.2.0-rc4-mglru-kmemlk-patch-zhaoyang3+ root=/dev/mapper/almalinux_desktop--mtodorov-root ro crashkernel=auto resume=/dev/mapper/almalinux_desktop--mtodorov-swap rd.lvm.lv=almalinux_desktop-mtodorov/root rd.lvm.lv=almalinux_desktop-mtodorov/swap loglevel=7 i915.alpha_support=1
[    0.032977] Unknown kernel command line parameters "BOOT_IMAGE=(hd0,gpt5)/vmlinuz-6.2.0-rc4-mglru-kmemlk-patch-zhaoyang3+", will be passed to user space.
[    0.033780] Dentry cache hash table entries: 2097152 (order: 12, 16777216 bytes, linear)
[    0.034158] Inode-cache hash table entries: 1048576 (order: 11, 8388608 bytes, linear)
[    0.034250] mem auto-init: stack:off, heap alloc:on, heap free:off
[    0.034640] stackdepot hash table entries: 1048576 (order: 11, 8388608 bytes, linear)
[    0.034647] software IO TLB: area num 8.
[    0.072295] Memory: 16143892K/16658536K available (18432K kernel code, 4118K rwdata, 7184K rodata, 4424K init, 7680K bss, 514384K reserved, 0K cma-reserved)

Nice work :-)

Thanks,
Mirsad

-- 
Mirsad Goran Todorovac
Sistem inženjer
Grafički fakultet | Akademija likovnih umjetnosti
Sveučilište u Zagrebu
 
System engineer
Faculty of Graphic Arts | Academy of Fine Arts
University of Zagreb, Republic of Croatia
The European Union