Re: [PATCH -next] mm/kmemleak: move the initialisation of object to __link_object

[Geert Uytterhoeven]

Hi Liu,

On Mon, Oct 23, 2023 at 3:52 AM Liu Shixin <liushixin2@xxxxxxxxxx> wrote:
> Leave __alloc_object() just do the actual allocation and __link_object()
> do the full initialisation.
>
> Suggested-by: Catalin Marinas <catalin.marinas@xxxxxxx>
> Signed-off-by: Liu Shixin <liushixin2@xxxxxxxxxx>

Thanks for your patch, which is now commit 245245c2fffd0050
("mm/kmemleak: move the initialisation of object to __link_object")
in v6.7-rc1.

I have bisected to this commit the BUG splat below (seen on various
platforms).  Reverting this commit fixes the issue.

 Memory: 7923468K/8257536K available (9024K kernel code, 5144K rwdata,
4088K rodata, 3072K init, 18331K bss, 268532K reserved, 65536K
cma-reserved)
 SLUB: HWalign=64, Order=0-3, MinObjects=0, CPUs=4, Nodes=1
+
+=============================
+[ BUG: Invalid wait context ]
+6.6.0-rc4-white-hawk-00387-g245245c2fffd #192 Not tainted
+-----------------------------
+swapper/0 is trying to lock:
+ffffffc0814bbed8 (&zone->lock){....}-{3:3}, at: __rmqueue_pcplist+0x4ac/0x53c
+other info that might help us debug this:
+context-{5:5}
+3 locks held by swapper/0:
+ #0: ffffffc0813cd720 (slab_mutex){....}-{4:4}, at:
kmem_cache_create_usercopy+0xac/0x2e0
+ #1: ffffffc0813d93e8 (kmemleak_lock){....}-{2:2}, at:
__create_object+0x48/0x98
+ #2: ffffff86bef6cc98 (&pcp->lock){....}-{3:3}, at:
get_page_from_freelist+0x184/0x7c0
+stack backtrace:
+CPU: 0 PID: 0 Comm: swapper Not tainted
6.6.0-rc4-white-hawk-00387-g245245c2fffd #192
+Hardware name: Renesas White Hawk CPU and Breakout boards based on
r8a779g0 (DT)
+Call trace:
+ dump_backtrace+0xac/0xe4
+ show_stack+0x14/0x20
+ dump_stack_lvl+0x68/0x94
+ dump_stack+0x14/0x1c
+ __lock_acquire+0x390/0xffc
+ lock_acquire+0x230/0x28c
+ _raw_spin_lock_irqsave+0x54/0x70
+ __rmqueue_pcplist+0x4ac/0x53c
+ get_page_from_freelist+0x2a8/0x7c0
+ __alloc_pages+0xf4/0x9f8
+ __stack_depot_save+0x178/0x3c8
+ stack_depot_save+0x10/0x18
+ set_track_prepare+0x44/0x70
+ __link_object+0xd0/0x220
+ __create_object+0x64/0x98
+ kmemleak_alloc+0x28/0x34
+ slab_post_alloc_hook.constprop.0+0xbc/0xc4
+ kmem_cache_alloc+0xd4/0x158
+ kmem_cache_create_usercopy+0x1c8/0x2e0
+ kmem_cache_create+0x18/0x20
+ kmemleak_init+0x74/0xfc
+ mm_core_init+0x214/0x250
+ start_kernel+0x2cc/0x4ec
+ __primary_switched+0xb4/0xbc
 trace event string verifier disabled
 Running RCU self tests

Gr{oetje,eeting}s,

                        Geert

-- 
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds