Messages in this thread Patch in this message | | | Date | Fri, 13 Jan 2023 09:41:05 +0100 | Subject | Re: 答复: INFO: [BISECTED] Regression: A Problem with /sys/kernel/debug/kmemleak output: backtrace not printed since 6.2.0-rc1 | From | Mirsad Goran Todorovac <> |
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On 13.1.2023. 7:20, 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.
Regards, Mirsad
-- Mirsad Todorovac System engineer Faculty of Graphic Arts | Academy of Fine Arts University of Zagreb Republic of Croatia, the European Union -- Sistem inženjer Grafički fakultet | Akademija likovnih umjetnosti Sveučilište u Zagrebu
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