lkml.org 
[lkml]   [2020]   [Feb]   [13]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH -next v2] mm/kmemleak: annotate various data races obj->ptr
On Thu, Feb 13, 2020 at 12:36:30PM -0500, Qian Cai wrote:
> The value of object->pointer could be accessed concurrently as noticed
> by KCSAN,
>
> write to 0xffffb0ea683a7d50 of 4 bytes by task 23575 on cpu 12:
> do_raw_spin_lock+0x114/0x200
> debug_spin_lock_after at kernel/locking/spinlock_debug.c:91
> (inlined by) do_raw_spin_lock at kernel/locking/spinlock_debug.c:115
> _raw_spin_lock+0x40/0x50
> __handle_mm_fault+0xa9e/0xd00
> handle_mm_fault+0xfc/0x2f0
> do_page_fault+0x263/0x6f9
> page_fault+0x34/0x40
>
> read to 0xffffb0ea683a7d50 of 4 bytes by task 839 on cpu 60:
> crc32_le_base+0x67/0x350
> crc32_le_base+0x67/0x350:
> crc32_body at lib/crc32.c:106
> (inlined by) crc32_le_generic at lib/crc32.c:179
> (inlined by) crc32_le at lib/crc32.c:197
> kmemleak_scan+0x528/0xd90
> update_checksum at mm/kmemleak.c:1172
> (inlined by) kmemleak_scan at mm/kmemleak.c:1497
> kmemleak_scan_thread+0xcc/0xfa
> kthread+0x1e0/0x200
> ret_from_fork+0x27/0x50
>
> write to 0xffff939bf07b95b8 of 4 bytes by interrupt on cpu 119:
> __free_object+0x884/0xcb0
> __free_object at lib/debugobjects.c:359
> __debug_check_no_obj_freed+0x19d/0x370
> debug_check_no_obj_freed+0x41/0x4b
> slab_free_freelist_hook+0xfb/0x1c0
> kmem_cache_free+0x10c/0x3a0
> free_object_rcu+0x1ca/0x260
> rcu_core+0x677/0xcc0
> rcu_core_si+0x17/0x20
> __do_softirq+0xd9/0x57c
> run_ksoftirqd+0x29/0x50
> smpboot_thread_fn+0x222/0x3f0
> kthread+0x1e0/0x200
> ret_from_fork+0x27/0x50
>
> read to 0xffff939bf07b95b8 of 8 bytes by task 838 on cpu 109:
> scan_block+0x69/0x190
> scan_block at mm/kmemleak.c:1250
> kmemleak_scan+0x249/0xd90
> scan_large_block at mm/kmemleak.c:1309
> (inlined by) kmemleak_scan at mm/kmemleak.c:1434
> kmemleak_scan_thread+0xcc/0xfa
> kthread+0x1e0/0x200
> ret_from_fork+0x27/0x50
>
> crc32() will dereference object->pointer. If a shattered value was
> returned due to a data race, it will be corrected in the next scan.
> scan_block() will dereference a range of addresses (e.g., percpu
> sections) to search for valid pointers. Even if a data race heppens, it
> will cause no issue because the code here does not care about the exact
> value of a non-pointer. Thus, mark them as intentional data races using
> the data_race() macro.
>
> Signed-off-by: Qian Cai <cai@lca.pw>

Acked-by: Catalin Marinas <catalin.marinas@arm.com>

\
 
 \ /
  Last update: 2020-02-13 18:39    [W:0.025 / U:0.036 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site