| Message ID | 20241105022747.2819151-1-koichiro.den@gmail.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | [v2] mm/slab: fix warning caused by duplicate kmem_cache creation in kmem_buckets_create | expand |
On Tue, Nov 05, 2024 at 11:27:47AM +0900, Koichiro Den wrote: > diff --git a/mm/slab_common.c b/mm/slab_common.c > index 3d26c257ed8b..db6ffe53c23e 100644 > --- a/mm/slab_common.c > +++ b/mm/slab_common.c > @@ -380,8 +380,11 @@ kmem_buckets *kmem_buckets_create(const char *name, slab_flags_t flags, > unsigned int usersize, > void (*ctor)(void *)) > { > + unsigned long mask = 0; > + unsigned int idx; > kmem_buckets *b; > - int idx; > + > + BUILD_BUG_ON(ARRAY_SIZE(kmalloc_caches[KMALLOC_NORMAL]) > BITS_PER_LONG); > > /* > * When the separate buckets API is not built in, just return > @@ -403,7 +406,7 @@ kmem_buckets *kmem_buckets_create(const char *name, slab_flags_t flags, > for (idx = 0; idx < ARRAY_SIZE(kmalloc_caches[KMALLOC_NORMAL]); idx++) { > char *short_size, *cache_name; > unsigned int cache_useroffset, cache_usersize; > - unsigned int size; > + unsigned int size, aligned_idx; > > if (!kmalloc_caches[KMALLOC_NORMAL][idx]) > continue; > @@ -416,10 +419,6 @@ kmem_buckets *kmem_buckets_create(const char *name, slab_flags_t flags, > if (WARN_ON(!short_size)) > goto fail; > > - cache_name = kasprintf(GFP_KERNEL, "%s-%s", name, short_size + 1); > - if (WARN_ON(!cache_name)) > - goto fail; > - > if (useroffset >= size) { > cache_useroffset = 0; > cache_usersize = 0; > @@ -427,18 +426,29 @@ kmem_buckets *kmem_buckets_create(const char *name, slab_flags_t flags, > cache_useroffset = useroffset; > cache_usersize = min(size - cache_useroffset, usersize); > } > - (*b)[idx] = kmem_cache_create_usercopy(cache_name, size, > - 0, flags, cache_useroffset, > - cache_usersize, ctor); > - kfree(cache_name); > - if (WARN_ON(!(*b)[idx])) > - goto fail; > + > + aligned_idx = __kmalloc_index(size, false); > + if (!(*b)[aligned_idx]) { > + cache_name = kasprintf(GFP_KERNEL, "%s-%s", name, short_size + 1); > + if (WARN_ON(!cache_name)) > + goto fail; > + (*b)[aligned_idx] = kmem_cache_create_usercopy(cache_name, size, > + 0, flags, cache_useroffset, > + cache_usersize, ctor); > + if (WARN_ON(!(*b)[aligned_idx])) { > + kfree(cache_name); > + goto fail; > + } > + set_bit(aligned_idx, &mask); > + } > + if (idx != aligned_idx) > + (*b)[idx] = (*b)[aligned_idx]; > } It looks fine. This pretty much matches the logic in new_kmalloc_cache() (from commit 963e84b0f262). > return b; > > fail: > - for (idx = 0; idx < ARRAY_SIZE(kmalloc_caches[KMALLOC_NORMAL]); idx++) > + for_each_set_bit(idx, &mask, ARRAY_SIZE(kmalloc_caches[KMALLOC_NORMAL])) > kmem_cache_destroy((*b)[idx]); > kmem_cache_free(kmem_buckets_cache, b); I gave this a try with swiotlb=noforce as well (which pushed the minimum alignment to 64). So: Reviewed-by: Catalin Marinas <catalin.marinas@arm.com> Tested-by: Catalin Marinas <catalin.marinas@arm.com>
On 11/5/24 03:27, Koichiro Den wrote: > Commit b035f5a6d852 ("mm: slab: reduce the kmalloc() minimum alignment > if DMA bouncing possible") reduced ARCH_KMALLOC_MINALIGN to 8 on arm64. > However, with KASAN_HW_TAGS enabled, arch_slab_minalign() becomes 16. > This causes kmalloc_caches[*][8] to be aliased to kmalloc_caches[*][16], > resulting in kmem_buckets_create() attempting to create a kmem_cache for > size 16 twice. This duplication triggers warnings on boot: > > [ 2.325108] ------------[ cut here ]------------ > [ 2.325135] kmem_cache of name 'memdup_user-16' already exists > [ 2.325783] WARNING: CPU: 0 PID: 1 at mm/slab_common.c:107 __kmem_cache_create_args+0xb8/0x3b0 > [ 2.327957] Modules linked in: > [ 2.328550] CPU: 0 UID: 0 PID: 1 Comm: swapper/0 Not tainted 6.12.0-rc5mm-unstable-arm64+ #12 > [ 2.328683] Hardware name: QEMU QEMU Virtual Machine, BIOS 2024.02-2 03/11/2024 > [ 2.328790] pstate: 61000009 (nZCv daif -PAN -UAO -TCO +DIT -SSBS BTYPE=--) > [ 2.328911] pc : __kmem_cache_create_args+0xb8/0x3b0 > [ 2.328930] lr : __kmem_cache_create_args+0xb8/0x3b0 > [ 2.328942] sp : ffff800083d6fc50 > [ 2.328961] x29: ffff800083d6fc50 x28: f2ff0000c1674410 x27: ffff8000820b0598 > [ 2.329061] x26: 000000007fffffff x25: 0000000000000010 x24: 0000000000002000 > [ 2.329101] x23: ffff800083d6fce8 x22: ffff8000832222e8 x21: ffff800083222388 > [ 2.329118] x20: f2ff0000c1674410 x19: f5ff0000c16364c0 x18: ffff800083d80030 > [ 2.329135] x17: 0000000000000000 x16: 0000000000000000 x15: 0000000000000000 > [ 2.329152] x14: 0000000000000000 x13: 0a73747369786520 x12: 79646165726c6120 > [ 2.329169] x11: 656820747563205b x10: 2d2d2d2d2d2d2d2d x9 : 0000000000000000 > [ 2.329194] x8 : 0000000000000000 x7 : 0000000000000000 x6 : 0000000000000000 > [ 2.329210] x5 : 0000000000000000 x4 : 0000000000000000 x3 : 0000000000000000 > [ 2.329226] x2 : 0000000000000000 x1 : 0000000000000000 x0 : 0000000000000000 > [ 2.329291] Call trace: > [ 2.329407] __kmem_cache_create_args+0xb8/0x3b0 > [ 2.329499] kmem_buckets_create+0xfc/0x320 > [ 2.329526] init_user_buckets+0x34/0x78 > [ 2.329540] do_one_initcall+0x64/0x3c8 > [ 2.329550] kernel_init_freeable+0x26c/0x578 > [ 2.329562] kernel_init+0x3c/0x258 > [ 2.329574] ret_from_fork+0x10/0x20 > [ 2.329698] ---[ end trace 0000000000000000 ]--- > > [ 2.403704] ------------[ cut here ]------------ > [ 2.404716] kmem_cache of name 'msg_msg-16' already exists > [ 2.404801] WARNING: CPU: 2 PID: 1 at mm/slab_common.c:107 __kmem_cache_create_args+0xb8/0x3b0 > [ 2.404842] Modules linked in: > [ 2.404971] CPU: 2 UID: 0 PID: 1 Comm: swapper/0 Tainted: G W 6.12.0-rc5mm-unstable-arm64+ #12 > [ 2.405026] Tainted: [W]=WARN > [ 2.405043] Hardware name: QEMU QEMU Virtual Machine, BIOS 2024.02-2 03/11/2024 > [ 2.405057] pstate: 60400009 (nZCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--) > [ 2.405079] pc : __kmem_cache_create_args+0xb8/0x3b0 > [ 2.405100] lr : __kmem_cache_create_args+0xb8/0x3b0 > [ 2.405111] sp : ffff800083d6fc50 > [ 2.405115] x29: ffff800083d6fc50 x28: fbff0000c1674410 x27: ffff8000820b0598 > [ 2.405135] x26: 000000000000ffd0 x25: 0000000000000010 x24: 0000000000006000 > [ 2.405153] x23: ffff800083d6fce8 x22: ffff8000832222e8 x21: ffff800083222388 > [ 2.405169] x20: fbff0000c1674410 x19: fdff0000c163d6c0 x18: ffff800083d80030 > [ 2.405185] x17: 0000000000000000 x16: 0000000000000000 x15: 0000000000000000 > [ 2.405201] x14: 0000000000000000 x13: 0a73747369786520 x12: 79646165726c6120 > [ 2.405217] x11: 656820747563205b x10: 2d2d2d2d2d2d2d2d x9 : 0000000000000000 > [ 2.405233] x8 : 0000000000000000 x7 : 0000000000000000 x6 : 0000000000000000 > [ 2.405248] x5 : 0000000000000000 x4 : 0000000000000000 x3 : 0000000000000000 > [ 2.405271] x2 : 0000000000000000 x1 : 0000000000000000 x0 : 0000000000000000 > [ 2.405287] Call trace: > [ 2.405293] __kmem_cache_create_args+0xb8/0x3b0 > [ 2.405305] kmem_buckets_create+0xfc/0x320 > [ 2.405315] init_msg_buckets+0x34/0x78 > [ 2.405326] do_one_initcall+0x64/0x3c8 > [ 2.405337] kernel_init_freeable+0x26c/0x578 > [ 2.405348] kernel_init+0x3c/0x258 > [ 2.405360] ret_from_fork+0x10/0x20 > [ 2.405370] ---[ end trace 0000000000000000 ]--- > > To address this, alias kmem_cache for sizes smaller than min alignment > to the aligned sized kmem_cache, as done with the default system kmalloc > bucket. > > Cc: <stable@vger.kernel.org> # 6.11.x > Fixes: b32801d1255b ("mm/slab: Introduce kmem_buckets_create() and family") > Signed-off-by: Koichiro Den <koichiro.den@gmail.com> Thanks. Given this warning was introduced in 6.12, I'm adding it to the slab/for-6.12-rc7/fixes branch so we fix it before 6.12 is final. > @@ -427,18 +426,29 @@ kmem_buckets *kmem_buckets_create(const char *name, slab_flags_t flags, > cache_useroffset = useroffset; > cache_usersize = min(size - cache_useroffset, usersize); > } > - (*b)[idx] = kmem_cache_create_usercopy(cache_name, size, > - 0, flags, cache_useroffset, > - cache_usersize, ctor); > - kfree(cache_name); > - if (WARN_ON(!(*b)[idx])) > - goto fail; > + > + aligned_idx = __kmalloc_index(size, false); > + if (!(*b)[aligned_idx]) { > + cache_name = kasprintf(GFP_KERNEL, "%s-%s", name, short_size + 1); > + if (WARN_ON(!cache_name)) > + goto fail; > + (*b)[aligned_idx] = kmem_cache_create_usercopy(cache_name, size, > + 0, flags, cache_useroffset, > + cache_usersize, ctor); > + if (WARN_ON(!(*b)[aligned_idx])) { > + kfree(cache_name); Note we need to free cache_name always, because kmem_cache_create() does a kstrdup_const(), so your change would be creating a memory leak. I've fixed it up locally. Vlastimil > + goto fail; > + } > + set_bit(aligned_idx, &mask); > + } > + if (idx != aligned_idx) > + (*b)[idx] = (*b)[aligned_idx]; > } > > return b; > > fail: > - for (idx = 0; idx < ARRAY_SIZE(kmalloc_caches[KMALLOC_NORMAL]); idx++) > + for_each_set_bit(idx, &mask, ARRAY_SIZE(kmalloc_caches[KMALLOC_NORMAL])) > kmem_cache_destroy((*b)[idx]); > kmem_cache_free(kmem_buckets_cache, b); >
On Tue, Nov 05, 2024 at 05:48:56PM +0100, Vlastimil Babka wrote: > On 11/5/24 03:27, Koichiro Den wrote: > > Commit b035f5a6d852 ("mm: slab: reduce the kmalloc() minimum alignment > > if DMA bouncing possible") reduced ARCH_KMALLOC_MINALIGN to 8 on arm64. > > However, with KASAN_HW_TAGS enabled, arch_slab_minalign() becomes 16. > > This causes kmalloc_caches[*][8] to be aliased to kmalloc_caches[*][16], > > resulting in kmem_buckets_create() attempting to create a kmem_cache for > > size 16 twice. This duplication triggers warnings on boot: > > > > [ 2.325108] ------------[ cut here ]------------ > > [ 2.325135] kmem_cache of name 'memdup_user-16' already exists > > [ 2.325783] WARNING: CPU: 0 PID: 1 at mm/slab_common.c:107 __kmem_cache_create_args+0xb8/0x3b0 > > [ 2.327957] Modules linked in: > > [ 2.328550] CPU: 0 UID: 0 PID: 1 Comm: swapper/0 Not tainted 6.12.0-rc5mm-unstable-arm64+ #12 > > [ 2.328683] Hardware name: QEMU QEMU Virtual Machine, BIOS 2024.02-2 03/11/2024 > > [ 2.328790] pstate: 61000009 (nZCv daif -PAN -UAO -TCO +DIT -SSBS BTYPE=--) > > [ 2.328911] pc : __kmem_cache_create_args+0xb8/0x3b0 > > [ 2.328930] lr : __kmem_cache_create_args+0xb8/0x3b0 > > [ 2.328942] sp : ffff800083d6fc50 > > [ 2.328961] x29: ffff800083d6fc50 x28: f2ff0000c1674410 x27: ffff8000820b0598 > > [ 2.329061] x26: 000000007fffffff x25: 0000000000000010 x24: 0000000000002000 > > [ 2.329101] x23: ffff800083d6fce8 x22: ffff8000832222e8 x21: ffff800083222388 > > [ 2.329118] x20: f2ff0000c1674410 x19: f5ff0000c16364c0 x18: ffff800083d80030 > > [ 2.329135] x17: 0000000000000000 x16: 0000000000000000 x15: 0000000000000000 > > [ 2.329152] x14: 0000000000000000 x13: 0a73747369786520 x12: 79646165726c6120 > > [ 2.329169] x11: 656820747563205b x10: 2d2d2d2d2d2d2d2d x9 : 0000000000000000 > > [ 2.329194] x8 : 0000000000000000 x7 : 0000000000000000 x6 : 0000000000000000 > > [ 2.329210] x5 : 0000000000000000 x4 : 0000000000000000 x3 : 0000000000000000 > > [ 2.329226] x2 : 0000000000000000 x1 : 0000000000000000 x0 : 0000000000000000 > > [ 2.329291] Call trace: > > [ 2.329407] __kmem_cache_create_args+0xb8/0x3b0 > > [ 2.329499] kmem_buckets_create+0xfc/0x320 > > [ 2.329526] init_user_buckets+0x34/0x78 > > [ 2.329540] do_one_initcall+0x64/0x3c8 > > [ 2.329550] kernel_init_freeable+0x26c/0x578 > > [ 2.329562] kernel_init+0x3c/0x258 > > [ 2.329574] ret_from_fork+0x10/0x20 > > [ 2.329698] ---[ end trace 0000000000000000 ]--- > > > > [ 2.403704] ------------[ cut here ]------------ > > [ 2.404716] kmem_cache of name 'msg_msg-16' already exists > > [ 2.404801] WARNING: CPU: 2 PID: 1 at mm/slab_common.c:107 __kmem_cache_create_args+0xb8/0x3b0 > > [ 2.404842] Modules linked in: > > [ 2.404971] CPU: 2 UID: 0 PID: 1 Comm: swapper/0 Tainted: G W 6.12.0-rc5mm-unstable-arm64+ #12 > > [ 2.405026] Tainted: [W]=WARN > > [ 2.405043] Hardware name: QEMU QEMU Virtual Machine, BIOS 2024.02-2 03/11/2024 > > [ 2.405057] pstate: 60400009 (nZCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--) > > [ 2.405079] pc : __kmem_cache_create_args+0xb8/0x3b0 > > [ 2.405100] lr : __kmem_cache_create_args+0xb8/0x3b0 > > [ 2.405111] sp : ffff800083d6fc50 > > [ 2.405115] x29: ffff800083d6fc50 x28: fbff0000c1674410 x27: ffff8000820b0598 > > [ 2.405135] x26: 000000000000ffd0 x25: 0000000000000010 x24: 0000000000006000 > > [ 2.405153] x23: ffff800083d6fce8 x22: ffff8000832222e8 x21: ffff800083222388 > > [ 2.405169] x20: fbff0000c1674410 x19: fdff0000c163d6c0 x18: ffff800083d80030 > > [ 2.405185] x17: 0000000000000000 x16: 0000000000000000 x15: 0000000000000000 > > [ 2.405201] x14: 0000000000000000 x13: 0a73747369786520 x12: 79646165726c6120 > > [ 2.405217] x11: 656820747563205b x10: 2d2d2d2d2d2d2d2d x9 : 0000000000000000 > > [ 2.405233] x8 : 0000000000000000 x7 : 0000000000000000 x6 : 0000000000000000 > > [ 2.405248] x5 : 0000000000000000 x4 : 0000000000000000 x3 : 0000000000000000 > > [ 2.405271] x2 : 0000000000000000 x1 : 0000000000000000 x0 : 0000000000000000 > > [ 2.405287] Call trace: > > [ 2.405293] __kmem_cache_create_args+0xb8/0x3b0 > > [ 2.405305] kmem_buckets_create+0xfc/0x320 > > [ 2.405315] init_msg_buckets+0x34/0x78 > > [ 2.405326] do_one_initcall+0x64/0x3c8 > > [ 2.405337] kernel_init_freeable+0x26c/0x578 > > [ 2.405348] kernel_init+0x3c/0x258 > > [ 2.405360] ret_from_fork+0x10/0x20 > > [ 2.405370] ---[ end trace 0000000000000000 ]--- > > > > To address this, alias kmem_cache for sizes smaller than min alignment > > to the aligned sized kmem_cache, as done with the default system kmalloc > > bucket. > > > > Cc: <stable@vger.kernel.org> # 6.11.x > > Fixes: b32801d1255b ("mm/slab: Introduce kmem_buckets_create() and family") > > Signed-off-by: Koichiro Den <koichiro.den@gmail.com> > > Thanks. Given this warning was introduced in 6.12, I'm adding it to the > slab/for-6.12-rc7/fixes branch so we fix it before 6.12 is final. > > > @@ -427,18 +426,29 @@ kmem_buckets *kmem_buckets_create(const char *name, slab_flags_t flags, > > cache_useroffset = useroffset; > > cache_usersize = min(size - cache_useroffset, usersize); > > } > > - (*b)[idx] = kmem_cache_create_usercopy(cache_name, size, > > - 0, flags, cache_useroffset, > > - cache_usersize, ctor); > > - kfree(cache_name); > > - if (WARN_ON(!(*b)[idx])) > > - goto fail; > > + > > + aligned_idx = __kmalloc_index(size, false); > > + if (!(*b)[aligned_idx]) { > > + cache_name = kasprintf(GFP_KERNEL, "%s-%s", name, short_size + 1); > > + if (WARN_ON(!cache_name)) > > + goto fail; > > + (*b)[aligned_idx] = kmem_cache_create_usercopy(cache_name, size, > > + 0, flags, cache_useroffset, > > + cache_usersize, ctor); > > + if (WARN_ON(!(*b)[aligned_idx])) { > > + kfree(cache_name); > > Note we need to free cache_name always, because kmem_cache_create() does a > kstrdup_const(), so your change would be creating a memory leak. I've fixed > it up locally. > > Vlastimil Ugh, sorry about that. Thanks. > > > + goto fail; > > + } > > + set_bit(aligned_idx, &mask); > > + } > > + if (idx != aligned_idx) > > + (*b)[idx] = (*b)[aligned_idx]; > > } > > > > return b; > > > > fail: > > - for (idx = 0; idx < ARRAY_SIZE(kmalloc_caches[KMALLOC_NORMAL]); idx++) > > + for_each_set_bit(idx, &mask, ARRAY_SIZE(kmalloc_caches[KMALLOC_NORMAL])) > > kmem_cache_destroy((*b)[idx]); > > kmem_cache_free(kmem_buckets_cache, b); > > >
diff --git a/mm/slab_common.c b/mm/slab_common.c index 3d26c257ed8b..db6ffe53c23e 100644 --- a/mm/slab_common.c +++ b/mm/slab_common.c @@ -380,8 +380,11 @@ kmem_buckets *kmem_buckets_create(const char *name, slab_flags_t flags, unsigned int usersize, void (*ctor)(void *)) { + unsigned long mask = 0; + unsigned int idx; kmem_buckets *b; - int idx; + + BUILD_BUG_ON(ARRAY_SIZE(kmalloc_caches[KMALLOC_NORMAL]) > BITS_PER_LONG); /* * When the separate buckets API is not built in, just return @@ -403,7 +406,7 @@ kmem_buckets *kmem_buckets_create(const char *name, slab_flags_t flags, for (idx = 0; idx < ARRAY_SIZE(kmalloc_caches[KMALLOC_NORMAL]); idx++) { char *short_size, *cache_name; unsigned int cache_useroffset, cache_usersize; - unsigned int size; + unsigned int size, aligned_idx; if (!kmalloc_caches[KMALLOC_NORMAL][idx]) continue; @@ -416,10 +419,6 @@ kmem_buckets *kmem_buckets_create(const char *name, slab_flags_t flags, if (WARN_ON(!short_size)) goto fail; - cache_name = kasprintf(GFP_KERNEL, "%s-%s", name, short_size + 1); - if (WARN_ON(!cache_name)) - goto fail; - if (useroffset >= size) { cache_useroffset = 0; cache_usersize = 0; @@ -427,18 +426,29 @@ kmem_buckets *kmem_buckets_create(const char *name, slab_flags_t flags, cache_useroffset = useroffset; cache_usersize = min(size - cache_useroffset, usersize); } - (*b)[idx] = kmem_cache_create_usercopy(cache_name, size, - 0, flags, cache_useroffset, - cache_usersize, ctor); - kfree(cache_name); - if (WARN_ON(!(*b)[idx])) - goto fail; + + aligned_idx = __kmalloc_index(size, false); + if (!(*b)[aligned_idx]) { + cache_name = kasprintf(GFP_KERNEL, "%s-%s", name, short_size + 1); + if (WARN_ON(!cache_name)) + goto fail; + (*b)[aligned_idx] = kmem_cache_create_usercopy(cache_name, size, + 0, flags, cache_useroffset, + cache_usersize, ctor); + if (WARN_ON(!(*b)[aligned_idx])) { + kfree(cache_name); + goto fail; + } + set_bit(aligned_idx, &mask); + } + if (idx != aligned_idx) + (*b)[idx] = (*b)[aligned_idx]; } return b; fail: - for (idx = 0; idx < ARRAY_SIZE(kmalloc_caches[KMALLOC_NORMAL]); idx++) + for_each_set_bit(idx, &mask, ARRAY_SIZE(kmalloc_caches[KMALLOC_NORMAL])) kmem_cache_destroy((*b)[idx]); kmem_cache_free(kmem_buckets_cache, b);
Commit b035f5a6d852 ("mm: slab: reduce the kmalloc() minimum alignment if DMA bouncing possible") reduced ARCH_KMALLOC_MINALIGN to 8 on arm64. However, with KASAN_HW_TAGS enabled, arch_slab_minalign() becomes 16. This causes kmalloc_caches[*][8] to be aliased to kmalloc_caches[*][16], resulting in kmem_buckets_create() attempting to create a kmem_cache for size 16 twice. This duplication triggers warnings on boot: [ 2.325108] ------------[ cut here ]------------ [ 2.325135] kmem_cache of name 'memdup_user-16' already exists [ 2.325783] WARNING: CPU: 0 PID: 1 at mm/slab_common.c:107 __kmem_cache_create_args+0xb8/0x3b0 [ 2.327957] Modules linked in: [ 2.328550] CPU: 0 UID: 0 PID: 1 Comm: swapper/0 Not tainted 6.12.0-rc5mm-unstable-arm64+ #12 [ 2.328683] Hardware name: QEMU QEMU Virtual Machine, BIOS 2024.02-2 03/11/2024 [ 2.328790] pstate: 61000009 (nZCv daif -PAN -UAO -TCO +DIT -SSBS BTYPE=--) [ 2.328911] pc : __kmem_cache_create_args+0xb8/0x3b0 [ 2.328930] lr : __kmem_cache_create_args+0xb8/0x3b0 [ 2.328942] sp : ffff800083d6fc50 [ 2.328961] x29: ffff800083d6fc50 x28: f2ff0000c1674410 x27: ffff8000820b0598 [ 2.329061] x26: 000000007fffffff x25: 0000000000000010 x24: 0000000000002000 [ 2.329101] x23: ffff800083d6fce8 x22: ffff8000832222e8 x21: ffff800083222388 [ 2.329118] x20: f2ff0000c1674410 x19: f5ff0000c16364c0 x18: ffff800083d80030 [ 2.329135] x17: 0000000000000000 x16: 0000000000000000 x15: 0000000000000000 [ 2.329152] x14: 0000000000000000 x13: 0a73747369786520 x12: 79646165726c6120 [ 2.329169] x11: 656820747563205b x10: 2d2d2d2d2d2d2d2d x9 : 0000000000000000 [ 2.329194] x8 : 0000000000000000 x7 : 0000000000000000 x6 : 0000000000000000 [ 2.329210] x5 : 0000000000000000 x4 : 0000000000000000 x3 : 0000000000000000 [ 2.329226] x2 : 0000000000000000 x1 : 0000000000000000 x0 : 0000000000000000 [ 2.329291] Call trace: [ 2.329407] __kmem_cache_create_args+0xb8/0x3b0 [ 2.329499] kmem_buckets_create+0xfc/0x320 [ 2.329526] init_user_buckets+0x34/0x78 [ 2.329540] do_one_initcall+0x64/0x3c8 [ 2.329550] kernel_init_freeable+0x26c/0x578 [ 2.329562] kernel_init+0x3c/0x258 [ 2.329574] ret_from_fork+0x10/0x20 [ 2.329698] ---[ end trace 0000000000000000 ]--- [ 2.403704] ------------[ cut here ]------------ [ 2.404716] kmem_cache of name 'msg_msg-16' already exists [ 2.404801] WARNING: CPU: 2 PID: 1 at mm/slab_common.c:107 __kmem_cache_create_args+0xb8/0x3b0 [ 2.404842] Modules linked in: [ 2.404971] CPU: 2 UID: 0 PID: 1 Comm: swapper/0 Tainted: G W 6.12.0-rc5mm-unstable-arm64+ #12 [ 2.405026] Tainted: [W]=WARN [ 2.405043] Hardware name: QEMU QEMU Virtual Machine, BIOS 2024.02-2 03/11/2024 [ 2.405057] pstate: 60400009 (nZCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--) [ 2.405079] pc : __kmem_cache_create_args+0xb8/0x3b0 [ 2.405100] lr : __kmem_cache_create_args+0xb8/0x3b0 [ 2.405111] sp : ffff800083d6fc50 [ 2.405115] x29: ffff800083d6fc50 x28: fbff0000c1674410 x27: ffff8000820b0598 [ 2.405135] x26: 000000000000ffd0 x25: 0000000000000010 x24: 0000000000006000 [ 2.405153] x23: ffff800083d6fce8 x22: ffff8000832222e8 x21: ffff800083222388 [ 2.405169] x20: fbff0000c1674410 x19: fdff0000c163d6c0 x18: ffff800083d80030 [ 2.405185] x17: 0000000000000000 x16: 0000000000000000 x15: 0000000000000000 [ 2.405201] x14: 0000000000000000 x13: 0a73747369786520 x12: 79646165726c6120 [ 2.405217] x11: 656820747563205b x10: 2d2d2d2d2d2d2d2d x9 : 0000000000000000 [ 2.405233] x8 : 0000000000000000 x7 : 0000000000000000 x6 : 0000000000000000 [ 2.405248] x5 : 0000000000000000 x4 : 0000000000000000 x3 : 0000000000000000 [ 2.405271] x2 : 0000000000000000 x1 : 0000000000000000 x0 : 0000000000000000 [ 2.405287] Call trace: [ 2.405293] __kmem_cache_create_args+0xb8/0x3b0 [ 2.405305] kmem_buckets_create+0xfc/0x320 [ 2.405315] init_msg_buckets+0x34/0x78 [ 2.405326] do_one_initcall+0x64/0x3c8 [ 2.405337] kernel_init_freeable+0x26c/0x578 [ 2.405348] kernel_init+0x3c/0x258 [ 2.405360] ret_from_fork+0x10/0x20 [ 2.405370] ---[ end trace 0000000000000000 ]--- To address this, alias kmem_cache for sizes smaller than min alignment to the aligned sized kmem_cache, as done with the default system kmalloc bucket. Cc: <stable@vger.kernel.org> # 6.11.x Fixes: b32801d1255b ("mm/slab: Introduce kmem_buckets_create() and family") Signed-off-by: Koichiro Den <koichiro.den@gmail.com> --- Changes in v2: - Simplify by just reusing calculated aligned size stored in the default kmalloc_caches --- mm/slab_common.c | 36 +++++++++++++++++++++++------------- 1 file changed, 23 insertions(+), 13 deletions(-)