Messages in this thread | | | Date | Tue, 13 Sep 2022 11:42:04 +0800 | Subject | Re: [PATCH] mm/slub: fix to return errno if kmalloc() fails | From | Chao Yu <> |
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On 2022/9/10 0:47, Christophe JAILLET wrote: > Le 30/08/2022 à 16:10, Chao Yu a écrit : >> From: Chao Yu <chao.yu@oppo.com> >> >> In create_unique_id(), kmalloc(, GFP_KERNEL) can fail due to >> out-of-memory, if it fails, return errno correctly rather than >> triggering panic via BUG_ON(); >> >> kernel BUG at mm/slub.c:5893! >> Internal error: Oops - BUG: 0 [#1] PREEMPT SMP >> >> Call trace: >> sysfs_slab_add+0x258/0x260 mm/slub.c:5973 >> __kmem_cache_create+0x60/0x118 mm/slub.c:4899 >> create_cache mm/slab_common.c:229 [inline] >> kmem_cache_create_usercopy+0x19c/0x31c mm/slab_common.c:335 >> kmem_cache_create+0x1c/0x28 mm/slab_common.c:390 >> f2fs_kmem_cache_create fs/f2fs/f2fs.h:2766 [inline] >> f2fs_init_xattr_caches+0x78/0xb4 fs/f2fs/xattr.c:808 >> f2fs_fill_super+0x1050/0x1e0c fs/f2fs/super.c:4149 >> mount_bdev+0x1b8/0x210 fs/super.c:1400 >> f2fs_mount+0x44/0x58 fs/f2fs/super.c:4512 >> legacy_get_tree+0x30/0x74 fs/fs_context.c:610 >> vfs_get_tree+0x40/0x140 fs/super.c:1530 >> do_new_mount+0x1dc/0x4e4 fs/namespace.c:3040 >> path_mount+0x358/0x914 fs/namespace.c:3370 >> do_mount fs/namespace.c:3383 [inline] >> __do_sys_mount fs/namespace.c:3591 [inline] >> __se_sys_mount fs/namespace.c:3568 [inline] >> __arm64_sys_mount+0x2f8/0x408 fs/namespace.c:3568 >> >> Cc: <stable@kernel.org> >> Reported-by: syzbot+81684812ea68216e08c5@syzkaller.appspotmail.com >> Signed-off-by: Chao Yu <chao.yu@oppo.com> >> --- >> mm/slub.c | 5 ++++- >> 1 file changed, 4 insertions(+), 1 deletion(-) >> >> diff --git a/mm/slub.c b/mm/slub.c >> index 862dbd9af4f5..e6f3727b9ad2 100644 >> --- a/mm/slub.c >> +++ b/mm/slub.c >> @@ -5890,7 +5890,8 @@ static char *create_unique_id(struct kmem_cache *s) >> char *name = kmalloc(ID_STR_LENGTH, GFP_KERNEL); > > Hi, > > looks that ID_STR_LENGTH could even be reduced to 32 or 16. > > The 2nd BUG_ON at the end of the function could certainly be just removed as well or remplaced by a: > if (p > name + ID_STR_LENGTH - 1) { > kfree(name); > return -E<something>; > }
Hi Christophe, Vlastimil,
Should I include this in v3? or may be in another patch?
Thanks,
> > Just my 2c, > > CJ > >> char *p = name; >> - BUG_ON(!name); >> + if (!name) >> + return ERR_PTR(-ENOMEM); >> *p++ = ':'; >> /* >> @@ -5948,6 +5949,8 @@ static int sysfs_slab_add(struct kmem_cache *s) >> * for the symlinks. >> */ >> name = create_unique_id(s); >> + if (IS_ERR(name)) >> + return PTR_ERR(name); >> } >> s->kobj.kset = kset; >
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