/sys/kernel/debug/kmemleak output: backtrace not printed since 6.2.0-rc1Please try the patch below if the configs are right. I think it should be caused by the late ready for kmemleak
On 12. 01. 2023. 20:50, Mirsad Todorovac wrote:
Hi all,/sys/kernel/debug/kmemleak:
there seems to be a problem with the output of
with the list of memory leaks.
[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
enabled
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
on a vanilla mainstream kernel from Mr. Torvalds' tree. I don't knowdeliberate feature for some reason or a bug.
if this is
implement
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@xxxxxxxxxx>
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:
writeback mechanism for zsmalloc git bisect goodstack_depot
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
for recording kmemleak's backtrace git bisect badfree
56a61617dd2276cbc56a6c868599716386d70041
# good: [61b963b52f59524e27692bc1c14bfb2459e32eb3] mm/gup_test:
memory allocated via kvcalloc() using kvfree() git bisect gooduse
61b963b52f59524e27692bc1c14bfb2459e32eb3
# first bad commit: [56a61617dd2276cbc56a6c868599716386d70041] mm:
stack_depot for recording kmemleak's backtrace # good:use
[9102b78b6f6ae6af3557114c265c266b312c1319] maple_tree: update
copyright dates for test code git bisect good
9102b78b6f6ae6af3557114c265c266b312c1319
# first bad commit: [56a61617dd2276cbc56a6c868599716386d70041] mm:
stack_depot for recording kmemleak's backtrace You have mail in(LENOVO_MT_10TX_BU_Lenovo_FM_V530S-07ICB)
/var/mail/mtodorov mtodorov@domac:~/linux/kernel/linux_torvalds$
The platform is 10TX000VCR
running AlmaLinux 8.7 (CentOS clone) and BIOS M22KT49A.PARTICULAR PURPOSE.
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
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?
commit 556eb1927da99ab366e370d593fc32da946768c3
Author: Zhaoyang Huang <zhaoyang.huang@xxxxxxxxxx>
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;
}