| Message ID | 20240923080211.820185-1-andrej.skvortzov@gmail.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | zram: don't free statically defined names | expand |
On (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).
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.
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
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; }
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(-)