drivers/block/zram/zram_drv.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)
The change is similar to that is used in comp_algorithm_set.
This is detected by KASAN.
==================================================================
Unable to handle kernel paging request at virtual address ffffffffc1edc3c8
KASAN: maybe wild-memory-access in range
[0x0003fffe0f6e1e40-0x0003fffe0f6e1e47]
Mem abort info:
ESR = 0x0000000096000006
EC = 0x25: DABT (current EL), IL = 32 bits
SET = 0, FnV = 0
EA = 0, S1PTW = 0
FSC = 0x06: level 2 translation fault
Data abort info:
ISV = 0, ISS = 0x00000006, ISS2 = 0x00000000
CM = 0, WnR = 0, TnD = 0, TagAccess = 0
GCS = 0, Overlay = 0, DirtyBit = 0, Xs = 0
swapper pgtable: 4k pages, 48-bit VAs, pgdp=00000000427dc000
[ffffffffc1edc3c8] pgd=00000000430e7003, p4d=00000000430e7003,
pud=00000000430e8003, pmd=0000000000000000
Internal error: Oops: 0000000096000006 [#1] SMP
Tainted: [W]=WARN, [C]=CRAP, [N]=TEST
Hardware name: Pine64 PinePhone (1.2) (DT)
pstate: a0000005 (NzCv daif -PAN -UAO -TCO -DIT -SSBS BTYPE=--)
pc : kfree+0x60/0x3a0
lr : zram_destroy_comps+0x98/0x198 [zram]
sp : ffff800089b57450
x29: ffff800089b57460 x28: 0000000000000004 x27: ffff800082833010
x26: 1fffe00000c8039c x25: 1fffe00000ba5004 x24: ffff000005d28000
x23: ffff800082533178 x22: ffff80007b71eaa8 x21: ffff000006401ce8
x20: ffff80007b70f7a0 x19: ffffffffc1edc3c0 x18: 1ffff00010506d6b
x17: 0000000000000000 x16: 0000000000000000 x15: ffff8000808e85e4
x14: ffff8000808e8478 x13: ffff80008003fa50 x12: ffff80008003f87c
x11: ffff800080011550 x10: ffff800081ee63f0 x9 : ffff80007b71eaa8
x8 : ffff80008003fa50 x7 : ffff80008003f87c x6 : 00000018a10e2f30
x5 : 00ffffffffffffff x4 : ffff00000ec93200 x3 : ffff00000bbee6e0
x2 : 0000000000000000 x1 : 0000000000000000 x0 : fffffdffc0000000
Call trace:
kfree+0x60/0x3a0
zram_destroy_comps+0x98/0x198 [zram]
zram_reset_device+0x22c/0x4a8 [zram]
reset_store+0x1bc/0x2d8 [zram]
dev_attr_store+0x44/0x80
sysfs_kf_write+0xfc/0x188
kernfs_fop_write_iter+0x28c/0x428
vfs_write+0x4dc/0x9b8
ksys_write+0x100/0x1f8
__arm64_sys_write+0x74/0xb8
invoke_syscall+0xd8/0x260
el0_svc_common.constprop.0+0xb4/0x240
do_el0_svc+0x48/0x68
el0_svc+0x40/0xc8
el0t_64_sync_handler+0x120/0x130
el0t_64_sync+0x190/0x198
Code: b26287e0 d34cfe73 f2dfbfe0 8b131813 (f9400660)
==================================================================
Signed-off-by: Andrey Skvortsov <andrej.skvortzov@gmail.com>
Fixes: 684826f8271a ("zram: free secondary algorithms names")
Cc: <stable@vger.kernel.org>
---
drivers/block/zram/zram_drv.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c
index c3d245617083d..d9d2c36658f59 100644
--- a/drivers/block/zram/zram_drv.c
+++ b/drivers/block/zram/zram_drv.c
@@ -2116,7 +2116,9 @@ static void zram_destroy_comps(struct zram *zram)
}
for (prio = ZRAM_SECONDARY_COMP; prio < ZRAM_MAX_COMPS; prio++) {
- kfree(zram->comp_algs[prio]);
+ /* Do not free statically defined compression algorithms */
+ if (zram->comp_algs[prio] != default_compressor)
+ kfree(zram->comp_algs[prio]);
zram->comp_algs[prio] = NULL;
}
--
2.45.2On (24/09/23 11:02), Andrey Skvortsov wrote:
> The change is similar to that is used in comp_algorithm_set.
> This is detected by KASAN.
>
> ==================================================================
---8<---
> Unable to handle kernel paging request at virtual address ffffffffc1edc3c8
> KASAN: maybe wild-memory-access in range
> [0x0003fffe0f6e1e40-0x0003fffe0f6e1e47]
> Mem abort info:
> ESR = 0x0000000096000006
> EC = 0x25: DABT (current EL), IL = 32 bits
> SET = 0, FnV = 0
> EA = 0, S1PTW = 0
> FSC = 0x06: level 2 translation fault
> Data abort info:
> ISV = 0, ISS = 0x00000006, ISS2 = 0x00000000
> CM = 0, WnR = 0, TnD = 0, TagAccess = 0
> GCS = 0, Overlay = 0, DirtyBit = 0, Xs = 0
> swapper pgtable: 4k pages, 48-bit VAs, pgdp=00000000427dc000
> [ffffffffc1edc3c8] pgd=00000000430e7003, p4d=00000000430e7003,
> pud=00000000430e8003, pmd=0000000000000000
> Internal error: Oops: 0000000096000006 [#1] SMP
>
> Tainted: [W]=WARN, [C]=CRAP, [N]=TEST
> Hardware name: Pine64 PinePhone (1.2) (DT)
> pstate: a0000005 (NzCv daif -PAN -UAO -TCO -DIT -SSBS BTYPE=--)
> pc : kfree+0x60/0x3a0
> lr : zram_destroy_comps+0x98/0x198 [zram]
> sp : ffff800089b57450
> x29: ffff800089b57460 x28: 0000000000000004 x27: ffff800082833010
> x26: 1fffe00000c8039c x25: 1fffe00000ba5004 x24: ffff000005d28000
> x23: ffff800082533178 x22: ffff80007b71eaa8 x21: ffff000006401ce8
> x20: ffff80007b70f7a0 x19: ffffffffc1edc3c0 x18: 1ffff00010506d6b
> x17: 0000000000000000 x16: 0000000000000000 x15: ffff8000808e85e4
> x14: ffff8000808e8478 x13: ffff80008003fa50 x12: ffff80008003f87c
> x11: ffff800080011550 x10: ffff800081ee63f0 x9 : ffff80007b71eaa8
> x8 : ffff80008003fa50 x7 : ffff80008003f87c x6 : 00000018a10e2f30
> x5 : 00ffffffffffffff x4 : ffff00000ec93200 x3 : ffff00000bbee6e0
> x2 : 0000000000000000 x1 : 0000000000000000 x0 : fffffdffc0000000
---8<---
The above is not needed in the commit message (not even sure if the
backtrace below is relevant).
> Call trace:
> kfree+0x60/0x3a0
> zram_destroy_comps+0x98/0x198 [zram]
> zram_reset_device+0x22c/0x4a8 [zram]
> reset_store+0x1bc/0x2d8 [zram]
> dev_attr_store+0x44/0x80
> sysfs_kf_write+0xfc/0x188
> kernfs_fop_write_iter+0x28c/0x428
> vfs_write+0x4dc/0x9b8
> ksys_write+0x100/0x1f8
> __arm64_sys_write+0x74/0xb8
> invoke_syscall+0xd8/0x260
> el0_svc_common.constprop.0+0xb4/0x240
> do_el0_svc+0x48/0x68
> el0_svc+0x40/0xc8
> el0t_64_sync_handler+0x120/0x130
> el0t_64_sync+0x190/0x198
[..]
> diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c
> index c3d245617083d..d9d2c36658f59 100644
> --- a/drivers/block/zram/zram_drv.c
> +++ b/drivers/block/zram/zram_drv.c
> @@ -2116,7 +2116,9 @@ static void zram_destroy_comps(struct zram *zram)
> }
>
> for (prio = ZRAM_SECONDARY_COMP; prio < ZRAM_MAX_COMPS; prio++) {
> - kfree(zram->comp_algs[prio]);
> + /* Do not free statically defined compression algorithms */
We probably don't really need this comment.
> + if (zram->comp_algs[prio] != default_compressor)
> + kfree(zram->comp_algs[prio]);
> zram->comp_algs[prio] = NULL;
> }
OK, so... I wonder how do you get a `default_compressor` on a
non-ZRAM_PRIMARY_COMP prio. May I ask what's your reproducer?
I didn't expect `default_compressor` on ZRAM_SECONDARY_COMP
and below. As far as I can tell, we only do this:
comp_algorithm_set(zram, ZRAM_PRIMARY_COMP, default_compressor);
in zram_reset_device() and zram_add(). So, how does it end up in
ZRAM_SECONDARY_COMP...
** Re-sending properly, somehow I managed to badly mess up
the headers the first time, sorry ***
On (24/09/24 00:34), Sergey Senozhatsky wrote:
> On (24/09/23 11:02), Andrey Skvortsov wrote:
> > for (prio = ZRAM_SECONDARY_COMP; prio < ZRAM_MAX_COMPS; prio++) {
> > - kfree(zram->comp_algs[prio]);
> > + /* Do not free statically defined compression algorithms */
>
> We probably don't really need this comment.
>
> > + if (zram->comp_algs[prio] != default_compressor)
> > + kfree(zram->comp_algs[prio]);
> > zram->comp_algs[prio] = NULL;
> > }
>
> OK, so... I wonder how do you get a `default_compressor` on a
> non-ZRAM_PRIMARY_COMP prio. May I ask what's your reproducer?
>
> I didn't expect `default_compressor` on ZRAM_SECONDARY_COMP
> and below. As far as I can tell, we only do this:
>
> comp_algorithm_set(zram, ZRAM_PRIMARY_COMP, default_compressor);
>
> in zram_reset_device() and zram_add(). So, how does it end up in
> ZRAM_SECONDARY_COMP...
Ugh, I know what's happening. You don't have CONFIG_ZRAM_MULTI_COMP
so that ZRAM_PRIMARY_COMP and ZRAM_SECONDARY_COMP are the same thing.
Yeah, that all makes sense now, I haven't thought about it.
Can you please send v2 (with the feedback resolved).
Hi Sergey,
On 24-09-24 00:47, Sergey Senozhatsky wrote:
> ** Re-sending properly, somehow I managed to badly mess up
> the headers the first time, sorry ***
>
>
> On (24/09/24 00:34), Sergey Senozhatsky wrote:
> > On (24/09/23 11:02), Andrey Skvortsov wrote:
> > > for (prio = ZRAM_SECONDARY_COMP; prio < ZRAM_MAX_COMPS; prio++) {
> > > - kfree(zram->comp_algs[prio]);
> > > + /* Do not free statically defined compression algorithms */
> >
> > We probably don't really need this comment.
> >
> > > + if (zram->comp_algs[prio] != default_compressor)
> > > + kfree(zram->comp_algs[prio]);
> > > zram->comp_algs[prio] = NULL;
> > > }
> >
> > OK, so... I wonder how do you get a `default_compressor` on a
> > non-ZRAM_PRIMARY_COMP prio. May I ask what's your reproducer?
> >
> > I didn't expect `default_compressor` on ZRAM_SECONDARY_COMP
> > and below. As far as I can tell, we only do this:
> >
> > comp_algorithm_set(zram, ZRAM_PRIMARY_COMP, default_compressor);
> >
> > in zram_reset_device() and zram_add(). So, how does it end up in
> > ZRAM_SECONDARY_COMP...
>
> Ugh, I know what's happening. You don't have CONFIG_ZRAM_MULTI_COMP
> so that ZRAM_PRIMARY_COMP and ZRAM_SECONDARY_COMP are the same thing.
> Yeah, that all makes sense now, I haven't thought about it.
yes, I don't have CONFIG_ZRAM_MULTI_COMP set. I'll include your
comment into commit description for v2.
> Can you please send v2 (with the feedback resolved).
--
Best regards,
Andrey Skvortsov
On (24/09/23 18:55), Andrey Skvortsov wrote:
[..]
> > Ugh, I know what's happening. You don't have CONFIG_ZRAM_MULTI_COMP
> > so that ZRAM_PRIMARY_COMP and ZRAM_SECONDARY_COMP are the same thing.
> > Yeah, that all makes sense now, I haven't thought about it.
>
> yes, I don't have CONFIG_ZRAM_MULTI_COMP set. I'll include your
> comment into commit description for v2.
Thanks.
Can you do it something like the diff below? Let's iterate
->comp_algs from ZRAM_PRIMARY_COMP. I don't really mind the
"Do not free statically defined" comment, up to you.
And the commit message probably can stay that: on !CONFIG_ZRAM_MULTI_COMP
systems ZRAM_SECONDARY_COMP can hold default_compressor, because it's
the same offset as ZRAM_PRIMARY_COMP, so we need to make sure that we
don't attempt to kfree() the statically defined comp name.
---
diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c
index c3d245617083..ad9c9bc3ccfc 100644
--- a/drivers/block/zram/zram_drv.c
+++ b/drivers/block/zram/zram_drv.c
@@ -2115,8 +2115,10 @@ static void zram_destroy_comps(struct zram *zram)
zram->num_active_comps--;
}
- for (prio = ZRAM_SECONDARY_COMP; prio < ZRAM_MAX_COMPS; prio++) {
- kfree(zram->comp_algs[prio]);
+ for (prio = ZRAM_PRIMARY_COMP; prio < ZRAM_MAX_COMPS; prio++) {
+ /* Do not free statically defined compression algorithms */
+ if (zram->comp_algs[prio] != default_compressor)
+ kfree(zram->comp_algs[prio]);
zram->comp_algs[prio] = NULL;
}
On 24-09-24 01:07, Sergey Senozhatsky wrote:
> On (24/09/23 18:55), Andrey Skvortsov wrote:
> [..]
> > > Ugh, I know what's happening. You don't have CONFIG_ZRAM_MULTI_COMP
> > > so that ZRAM_PRIMARY_COMP and ZRAM_SECONDARY_COMP are the same thing.
> > > Yeah, that all makes sense now, I haven't thought about it.
> >
> > yes, I don't have CONFIG_ZRAM_MULTI_COMP set. I'll include your
> > comment into commit description for v2.
>
> Thanks.
>
> Can you do it something like the diff below? Let's iterate
> ->comp_algs from ZRAM_PRIMARY_COMP. I don't really mind the
> "Do not free statically defined" comment, up to you.
>
> And the commit message probably can stay that: on !CONFIG_ZRAM_MULTI_COMP
> systems ZRAM_SECONDARY_COMP can hold default_compressor, because it's
> the same offset as ZRAM_PRIMARY_COMP, so we need to make sure that we
> don't attempt to kfree() the statically defined comp name.
>
> ---
>
> diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c
> index c3d245617083..ad9c9bc3ccfc 100644
> --- a/drivers/block/zram/zram_drv.c
> +++ b/drivers/block/zram/zram_drv.c
> @@ -2115,8 +2115,10 @@ static void zram_destroy_comps(struct zram *zram)
> zram->num_active_comps--;
> }
>
> - for (prio = ZRAM_SECONDARY_COMP; prio < ZRAM_MAX_COMPS; prio++) {
> - kfree(zram->comp_algs[prio]);
> + for (prio = ZRAM_PRIMARY_COMP; prio < ZRAM_MAX_COMPS; prio++) {
> + /* Do not free statically defined compression algorithms */
> + if (zram->comp_algs[prio] != default_compressor)
> + kfree(zram->comp_algs[prio]);
> zram->comp_algs[prio] = NULL;
> }
Sorry, I've seen you comment after I've sent v2. I'll do this in v3.
--
Best regards,
Andrey Skvortsov
Le 23/09/2024 à 18:43, Andrey Skvortsov a écrit :
> On 24-09-24 01:07, Sergey Senozhatsky wrote:
>> On (24/09/23 18:55), Andrey Skvortsov wrote:
>> [..]
>>>> Ugh, I know what's happening. You don't have CONFIG_ZRAM_MULTI_COMP
>>>> so that ZRAM_PRIMARY_COMP and ZRAM_SECONDARY_COMP are the same thing.
>>>> Yeah, that all makes sense now, I haven't thought about it.
>>>
>>> yes, I don't have CONFIG_ZRAM_MULTI_COMP set. I'll include your
>>> comment into commit description for v2.
>>
>> Thanks.
>>
>> Can you do it something like the diff below? Let's iterate
>> ->comp_algs from ZRAM_PRIMARY_COMP. I don't really mind the
>> "Do not free statically defined" comment, up to you.
>>
>> And the commit message probably can stay that: on !CONFIG_ZRAM_MULTI_COMP
>> systems ZRAM_SECONDARY_COMP can hold default_compressor, because it's
>> the same offset as ZRAM_PRIMARY_COMP, so we need to make sure that we
>> don't attempt to kfree() the statically defined comp name.
>>
>> ---
>>
>> diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c
>> index c3d245617083..ad9c9bc3ccfc 100644
>> --- a/drivers/block/zram/zram_drv.c
>> +++ b/drivers/block/zram/zram_drv.c
>> @@ -2115,8 +2115,10 @@ static void zram_destroy_comps(struct zram *zram)
>> zram->num_active_comps--;
>> }
>>
>> - for (prio = ZRAM_SECONDARY_COMP; prio < ZRAM_MAX_COMPS; prio++) {
>> - kfree(zram->comp_algs[prio]);
>> + for (prio = ZRAM_PRIMARY_COMP; prio < ZRAM_MAX_COMPS; prio++) {
>> + /* Do not free statically defined compression algorithms */
>> + if (zram->comp_algs[prio] != default_compressor)
>> + kfree(zram->comp_algs[prio]);
>> zram->comp_algs[prio] = NULL;
>> }
> Sorry, I've seen you comment after I've sent v2. I'll do this in v3.
>
Hi,
maybe kfree_const() to catch potential future cases and simplify code?
CJ
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