From: Eric Dumazet <[email protected]>
syzbot reported access to unitialized memory in mbind() [1]
Issue came with commit bda420b98505 ("numa balancing: migrate on
fault among multiple bound nodes")
This commit added a new bit in MPOL_MODE_FLAGS, but only checked
valid combination (MPOL_F_NUMA_BALANCING can only be used with MPOL_BIND)
in do_set_mempolicy()
This patch moves the check in sanitize_mpol_flags() so that it
is also used by mbind()
[1]
BUG: KMSAN: uninit-value in __mpol_equal+0x567/0x590 mm/mempolicy.c:2260
__mpol_equal+0x567/0x590 mm/mempolicy.c:2260
mpol_equal include/linux/mempolicy.h:105 [inline]
vma_merge+0x4a1/0x1e60 mm/mmap.c:1190
mbind_range+0xcc8/0x1e80 mm/mempolicy.c:811
do_mbind+0xf42/0x15f0 mm/mempolicy.c:1333
kernel_mbind mm/mempolicy.c:1483 [inline]
__do_sys_mbind mm/mempolicy.c:1490 [inline]
__se_sys_mbind+0x437/0xb80 mm/mempolicy.c:1486
__x64_sys_mbind+0x19d/0x200 mm/mempolicy.c:1486
do_syscall_x64 arch/x86/entry/common.c:51 [inline]
do_syscall_64+0x54/0xd0 arch/x86/entry/common.c:82
entry_SYSCALL_64_after_hwframe+0x44/0xae
Uninit was created at:
slab_alloc_node mm/slub.c:3221 [inline]
slab_alloc mm/slub.c:3230 [inline]
kmem_cache_alloc+0x751/0xff0 mm/slub.c:3235
mpol_new mm/mempolicy.c:293 [inline]
do_mbind+0x912/0x15f0 mm/mempolicy.c:1289
kernel_mbind mm/mempolicy.c:1483 [inline]
__do_sys_mbind mm/mempolicy.c:1490 [inline]
__se_sys_mbind+0x437/0xb80 mm/mempolicy.c:1486
__x64_sys_mbind+0x19d/0x200 mm/mempolicy.c:1486
do_syscall_x64 arch/x86/entry/common.c:51 [inline]
do_syscall_64+0x54/0xd0 arch/x86/entry/common.c:82
entry_SYSCALL_64_after_hwframe+0x44/0xae
=====================================================
Kernel panic - not syncing: panic_on_kmsan set ...
CPU: 0 PID: 15049 Comm: syz-executor.0 Tainted: G B 5.15.0-rc2-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0x1ff/0x28e lib/dump_stack.c:106
dump_stack+0x25/0x28 lib/dump_stack.c:113
panic+0x44f/0xdeb kernel/panic.c:232
kmsan_report+0x2ee/0x300 mm/kmsan/report.c:186
__msan_warning+0xd7/0x150 mm/kmsan/instrumentation.c:208
__mpol_equal+0x567/0x590 mm/mempolicy.c:2260
mpol_equal include/linux/mempolicy.h:105 [inline]
vma_merge+0x4a1/0x1e60 mm/mmap.c:1190
mbind_range+0xcc8/0x1e80 mm/mempolicy.c:811
do_mbind+0xf42/0x15f0 mm/mempolicy.c:1333
kernel_mbind mm/mempolicy.c:1483 [inline]
__do_sys_mbind mm/mempolicy.c:1490 [inline]
__se_sys_mbind+0x437/0xb80 mm/mempolicy.c:1486
__x64_sys_mbind+0x19d/0x200 mm/mempolicy.c:1486
do_syscall_x64 arch/x86/entry/common.c:51 [inline]
do_syscall_64+0x54/0xd0 arch/x86/entry/common.c:82
entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x7f4a41b2c709
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 bc ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f4a3f0a3188 EFLAGS: 00000246 ORIG_RAX: 00000000000000ed
RAX: ffffffffffffffda RBX: 00007f4a41c30f60 RCX: 00007f4a41b2c709
RDX: 0000000000002001 RSI: 0000000000c00007 RDI: 0000000020012000
RBP: 00007f4a41b86cb4 R08: 0000000000000000 R09: 0000010000000002
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f4a42164b2f R14: 00007f4a3f0a3300 R15: 0000000000022000
Fixes: bda420b98505 ("numa balancing: migrate on fault among multiple bound nodes")
Signed-off-by: Eric Dumazet <[email protected]>
Reported-by: syzbot <[email protected]>
Cc: "Huang, Ying" <[email protected]>
Cc: Mel Gorman <[email protected]>
---
mm/mempolicy.c | 16 +++++-----------
1 file changed, 5 insertions(+), 11 deletions(-)
diff --git a/mm/mempolicy.c b/mm/mempolicy.c
index 1592b081c58ef6dd63c6f075ad24722f2be7cb5d..7a7abdbec7af66f88bb68cb4f47e9722d56bfd5b 100644
--- a/mm/mempolicy.c
+++ b/mm/mempolicy.c
@@ -856,16 +856,6 @@ static long do_set_mempolicy(unsigned short mode, unsigned short flags,
goto out;
}
- if (flags & MPOL_F_NUMA_BALANCING) {
- if (new && new->mode == MPOL_BIND) {
- new->flags |= (MPOL_F_MOF | MPOL_F_MORON);
- } else {
- ret = -EINVAL;
- mpol_put(new);
- goto out;
- }
- }
-
ret = mpol_set_nodemask(new, nodes, scratch);
if (ret) {
mpol_put(new);
@@ -1458,7 +1448,11 @@ static inline int sanitize_mpol_flags(int *mode, unsigned short *flags)
return -EINVAL;
if ((*flags & MPOL_F_STATIC_NODES) && (*flags & MPOL_F_RELATIVE_NODES))
return -EINVAL;
-
+ if (*flags & MPOL_F_NUMA_BALANCING) {
+ if (mode != MPOL_BIND)
+ return -EINVAL;
+ *flags |= (MPOL_F_MOF | MPOL_F_MORON);
+ }
return 0;
}
--
2.33.0.800.g4c38ced690-goog
Hi Eric,
I love your patch! Perhaps something to improve:
[auto build test WARNING on hnaz-mm/master]
url: https://github.com/0day-ci/linux/commits/Eric-Dumazet/mm-mempolicy-do-not-allow-illegal-MPOL_F_NUMA_BALANCING-MPOL_LOCAL-in-mbind/20211002-015054
base: https://github.com/hnaz/linux-mm master
config: ia64-defconfig (attached as .config)
compiler: ia64-linux-gcc (GCC) 11.2.0
reproduce (this is a W=1 build):
wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
chmod +x ~/bin/make.cross
# https://github.com/0day-ci/linux/commit/fe87354835a4bf5cad6d885f0ba558c767fee6f1
git remote add linux-review https://github.com/0day-ci/linux
git fetch --no-tags linux-review Eric-Dumazet/mm-mempolicy-do-not-allow-illegal-MPOL_F_NUMA_BALANCING-MPOL_LOCAL-in-mbind/20211002-015054
git checkout fe87354835a4bf5cad6d885f0ba558c767fee6f1
# save the attached .config to linux build tree
mkdir build_dir
COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-11.2.0 make.cross O=build_dir ARCH=ia64 SHELL=/bin/bash
If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <[email protected]>
All warnings (new ones prefixed by >>):
mm/mempolicy.c: In function 'sanitize_mpol_flags':
>> mm/mempolicy.c:1452:26: warning: comparison between pointer and integer
1452 | if (mode != MPOL_BIND)
| ^~
vim +1452 mm/mempolicy.c
1440
1441 /* Basic parameter sanity check used by both mbind() and set_mempolicy() */
1442 static inline int sanitize_mpol_flags(int *mode, unsigned short *flags)
1443 {
1444 *flags = *mode & MPOL_MODE_FLAGS;
1445 *mode &= ~MPOL_MODE_FLAGS;
1446
1447 if ((unsigned int)(*mode) >= MPOL_MAX)
1448 return -EINVAL;
1449 if ((*flags & MPOL_F_STATIC_NODES) && (*flags & MPOL_F_RELATIVE_NODES))
1450 return -EINVAL;
1451 if (*flags & MPOL_F_NUMA_BALANCING) {
> 1452 if (mode != MPOL_BIND)
1453 return -EINVAL;
1454 *flags |= (MPOL_F_MOF | MPOL_F_MORON);
1455 }
1456 return 0;
1457 }
1458
---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/[email protected]
On Fri, Oct 1, 2021 at 1:25 PM kernel test robot <[email protected]> wrote:
>
> Hi Eric,
>
> I love your patch! Perhaps something to improve:
>
> [auto build test WARNING on hnaz-mm/master]
>
> url: https://github.com/0day-ci/linux/commits/Eric-Dumazet/mm-mempolicy-do-not-allow-illegal-MPOL_F_NUMA_BALANCING-MPOL_LOCAL-in-mbind/20211002-015054
> base: https://github.com/hnaz/linux-mm master
> config: ia64-defconfig (attached as .config)
> compiler: ia64-linux-gcc (GCC) 11.2.0
> reproduce (this is a W=1 build):
> wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
> chmod +x ~/bin/make.cross
> # https://github.com/0day-ci/linux/commit/fe87354835a4bf5cad6d885f0ba558c767fee6f1
> git remote add linux-review https://github.com/0day-ci/linux
> git fetch --no-tags linux-review Eric-Dumazet/mm-mempolicy-do-not-allow-illegal-MPOL_F_NUMA_BALANCING-MPOL_LOCAL-in-mbind/20211002-015054
> git checkout fe87354835a4bf5cad6d885f0ba558c767fee6f1
> # save the attached .config to linux build tree
> mkdir build_dir
> COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-11.2.0 make.cross O=build_dir ARCH=ia64 SHELL=/bin/bash
>
> If you fix the issue, kindly add following tag as appropriate
> Reported-by: kernel test robot <[email protected]>
>
> All warnings (new ones prefixed by >>):
>
> mm/mempolicy.c: In function 'sanitize_mpol_flags':
> >> mm/mempolicy.c:1452:26: warning: comparison between pointer and integer
> 1452 | if (mode != MPOL_BIND)
> | ^~
Oh well, last minute changes, and indeed my compiler warned me while I
was away :/
mm/mempolicy.c:1452:12: warning: comparison between pointer and
integer ('int *' and 'int') [-Wpointer-integer-compare]
if (mode != MPOL_BIND)
~~~~ ^ ~~~~~~~~~
I am sending a v2, thanks.
>
>
> vim +1452 mm/mempolicy.c
>
> 1440
> 1441 /* Basic parameter sanity check used by both mbind() and set_mempolicy() */
> 1442 static inline int sanitize_mpol_flags(int *mode, unsigned short *flags)
> 1443 {
> 1444 *flags = *mode & MPOL_MODE_FLAGS;
> 1445 *mode &= ~MPOL_MODE_FLAGS;
> 1446
> 1447 if ((unsigned int)(*mode) >= MPOL_MAX)
> 1448 return -EINVAL;
> 1449 if ((*flags & MPOL_F_STATIC_NODES) && (*flags & MPOL_F_RELATIVE_NODES))
> 1450 return -EINVAL;
> 1451 if (*flags & MPOL_F_NUMA_BALANCING) {
> > 1452 if (mode != MPOL_BIND)
> 1453 return -EINVAL;
> 1454 *flags |= (MPOL_F_MOF | MPOL_F_MORON);
> 1455 }
> 1456 return 0;
> 1457 }
> 1458
>
> ---
> 0-DAY CI Kernel Test Service, Intel Corporation
> https://lists.01.org/hyperkitty/list/[email protected]
On Sat, Oct 2, 2021 at 1:49 AM Eric Dumazet <[email protected]> wrote:
>
> From: Eric Dumazet <[email protected]>
>
> syzbot reported access to unitialized memory in mbind() [1]
>
> Issue came with commit bda420b98505 ("numa balancing: migrate on
> fault among multiple bound nodes")
>
> This commit added a new bit in MPOL_MODE_FLAGS, but only checked
> valid combination (MPOL_F_NUMA_BALANCING can only be used with MPOL_BIND)
> in do_set_mempolicy()
>
> This patch moves the check in sanitize_mpol_flags() so that it
> is also used by mbind()
>
> [1]
> BUG: KMSAN: uninit-value in __mpol_equal+0x567/0x590 mm/mempolicy.c:2260
> __mpol_equal+0x567/0x590 mm/mempolicy.c:2260
> mpol_equal include/linux/mempolicy.h:105 [inline]
> vma_merge+0x4a1/0x1e60 mm/mmap.c:1190
> mbind_range+0xcc8/0x1e80 mm/mempolicy.c:811
> do_mbind+0xf42/0x15f0 mm/mempolicy.c:1333
> kernel_mbind mm/mempolicy.c:1483 [inline]
> __do_sys_mbind mm/mempolicy.c:1490 [inline]
> __se_sys_mbind+0x437/0xb80 mm/mempolicy.c:1486
> __x64_sys_mbind+0x19d/0x200 mm/mempolicy.c:1486
> do_syscall_x64 arch/x86/entry/common.c:51 [inline]
> do_syscall_64+0x54/0xd0 arch/x86/entry/common.c:82
> entry_SYSCALL_64_after_hwframe+0x44/0xae
>
> Uninit was created at:
> slab_alloc_node mm/slub.c:3221 [inline]
> slab_alloc mm/slub.c:3230 [inline]
> kmem_cache_alloc+0x751/0xff0 mm/slub.c:3235
> mpol_new mm/mempolicy.c:293 [inline]
> do_mbind+0x912/0x15f0 mm/mempolicy.c:1289
> kernel_mbind mm/mempolicy.c:1483 [inline]
> __do_sys_mbind mm/mempolicy.c:1490 [inline]
> __se_sys_mbind+0x437/0xb80 mm/mempolicy.c:1486
> __x64_sys_mbind+0x19d/0x200 mm/mempolicy.c:1486
> do_syscall_x64 arch/x86/entry/common.c:51 [inline]
> do_syscall_64+0x54/0xd0 arch/x86/entry/common.c:82
> entry_SYSCALL_64_after_hwframe+0x44/0xae
> =====================================================
> Kernel panic - not syncing: panic_on_kmsan set ...
> CPU: 0 PID: 15049 Comm: syz-executor.0 Tainted: G B 5.15.0-rc2-syzkaller #0
> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
> Call Trace:
> __dump_stack lib/dump_stack.c:88 [inline]
> dump_stack_lvl+0x1ff/0x28e lib/dump_stack.c:106
> dump_stack+0x25/0x28 lib/dump_stack.c:113
> panic+0x44f/0xdeb kernel/panic.c:232
> kmsan_report+0x2ee/0x300 mm/kmsan/report.c:186
> __msan_warning+0xd7/0x150 mm/kmsan/instrumentation.c:208
> __mpol_equal+0x567/0x590 mm/mempolicy.c:2260
> mpol_equal include/linux/mempolicy.h:105 [inline]
> vma_merge+0x4a1/0x1e60 mm/mmap.c:1190
> mbind_range+0xcc8/0x1e80 mm/mempolicy.c:811
> do_mbind+0xf42/0x15f0 mm/mempolicy.c:1333
> kernel_mbind mm/mempolicy.c:1483 [inline]
> __do_sys_mbind mm/mempolicy.c:1490 [inline]
> __se_sys_mbind+0x437/0xb80 mm/mempolicy.c:1486
> __x64_sys_mbind+0x19d/0x200 mm/mempolicy.c:1486
> do_syscall_x64 arch/x86/entry/common.c:51 [inline]
> do_syscall_64+0x54/0xd0 arch/x86/entry/common.c:82
> entry_SYSCALL_64_after_hwframe+0x44/0xae
> RIP: 0033:0x7f4a41b2c709
> Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 bc ff ff ff f7 d8 64 89 01 48
> RSP: 002b:00007f4a3f0a3188 EFLAGS: 00000246 ORIG_RAX: 00000000000000ed
> RAX: ffffffffffffffda RBX: 00007f4a41c30f60 RCX: 00007f4a41b2c709
> RDX: 0000000000002001 RSI: 0000000000c00007 RDI: 0000000020012000
> RBP: 00007f4a41b86cb4 R08: 0000000000000000 R09: 0000010000000002
> R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
> R13: 00007f4a42164b2f R14: 00007f4a3f0a3300 R15: 0000000000022000
>
Hi Eric,
this crash seems like the bug report [1] on Syzbot dashboard.
[1] https://syzkaller.appspot.com/bug?id=028833194204bb15c2c43d822b8f7401360d57f5
If yes, maybe you can push a patch testing request.
> Fixes: bda420b98505 ("numa balancing: migrate on fault among multiple bound nodes")
> Signed-off-by: Eric Dumazet <[email protected]>
> Reported-by: syzbot <[email protected]>
> Cc: "Huang, Ying" <[email protected]>
> Cc: Mel Gorman <[email protected]>
> ---
> mm/mempolicy.c | 16 +++++-----------
> 1 file changed, 5 insertions(+), 11 deletions(-)
>
> diff --git a/mm/mempolicy.c b/mm/mempolicy.c
> index 1592b081c58ef6dd63c6f075ad24722f2be7cb5d..7a7abdbec7af66f88bb68cb4f47e9722d56bfd5b 100644
> --- a/mm/mempolicy.c
> +++ b/mm/mempolicy.c
> @@ -856,16 +856,6 @@ static long do_set_mempolicy(unsigned short mode, unsigned short flags,
> goto out;
> }
>
> - if (flags & MPOL_F_NUMA_BALANCING) {
> - if (new && new->mode == MPOL_BIND) {
> - new->flags |= (MPOL_F_MOF | MPOL_F_MORON);
> - } else {
> - ret = -EINVAL;
> - mpol_put(new);
> - goto out;
> - }
> - }
> -
> ret = mpol_set_nodemask(new, nodes, scratch);
> if (ret) {
> mpol_put(new);
> @@ -1458,7 +1448,11 @@ static inline int sanitize_mpol_flags(int *mode, unsigned short *flags)
> return -EINVAL;
> if ((*flags & MPOL_F_STATIC_NODES) && (*flags & MPOL_F_RELATIVE_NODES))
> return -EINVAL;
> -
> + if (*flags & MPOL_F_NUMA_BALANCING) {
> + if (mode != MPOL_BIND)
> + return -EINVAL;
> + *flags |= (MPOL_F_MOF | MPOL_F_MORON);
> + }
> return 0;
> }
>
> --
> 2.33.0.800.g4c38ced690-goog
>
> --
> You received this message because you are subscribed to the Google Groups "syzkaller" group.
> To unsubscribe from this group and stop receiving emails from it, send an email to [email protected].
> To view this discussion on the web visit https://groups.google.com/d/msgid/syzkaller/20211001174947.135123-1-eric.dumazet%40gmail.com.
On Thu, Oct 7, 2021 at 10:26 PM Dongliang Mu <[email protected]> wrote:
>
> On Sat, Oct 2, 2021 at 1:49 AM Eric Dumazet <[email protected]> wrote:
> >
> > From: Eric Dumazet <[email protected]>
> >
> > syzbot reported access to unitialized memory in mbind() [1]
> >
> > Issue came with commit bda420b98505 ("numa balancing: migrate on
> > fault among multiple bound nodes")
> >
> > This commit added a new bit in MPOL_MODE_FLAGS, but only checked
> > valid combination (MPOL_F_NUMA_BALANCING can only be used with MPOL_BIND)
> > in do_set_mempolicy()
> >
> > This patch moves the check in sanitize_mpol_flags() so that it
> > is also used by mbind()
> >
> > [1]
> > BUG: KMSAN: uninit-value in __mpol_equal+0x567/0x590 mm/mempolicy.c:2260
> > __mpol_equal+0x567/0x590 mm/mempolicy.c:2260
> > mpol_equal include/linux/mempolicy.h:105 [inline]
> > vma_merge+0x4a1/0x1e60 mm/mmap.c:1190
> > mbind_range+0xcc8/0x1e80 mm/mempolicy.c:811
> > do_mbind+0xf42/0x15f0 mm/mempolicy.c:1333
> > kernel_mbind mm/mempolicy.c:1483 [inline]
> > __do_sys_mbind mm/mempolicy.c:1490 [inline]
> > __se_sys_mbind+0x437/0xb80 mm/mempolicy.c:1486
> > __x64_sys_mbind+0x19d/0x200 mm/mempolicy.c:1486
> > do_syscall_x64 arch/x86/entry/common.c:51 [inline]
> > do_syscall_64+0x54/0xd0 arch/x86/entry/common.c:82
> > entry_SYSCALL_64_after_hwframe+0x44/0xae
> >
> > Uninit was created at:
> > slab_alloc_node mm/slub.c:3221 [inline]
> > slab_alloc mm/slub.c:3230 [inline]
> > kmem_cache_alloc+0x751/0xff0 mm/slub.c:3235
> > mpol_new mm/mempolicy.c:293 [inline]
> > do_mbind+0x912/0x15f0 mm/mempolicy.c:1289
> > kernel_mbind mm/mempolicy.c:1483 [inline]
> > __do_sys_mbind mm/mempolicy.c:1490 [inline]
> > __se_sys_mbind+0x437/0xb80 mm/mempolicy.c:1486
> > __x64_sys_mbind+0x19d/0x200 mm/mempolicy.c:1486
> > do_syscall_x64 arch/x86/entry/common.c:51 [inline]
> > do_syscall_64+0x54/0xd0 arch/x86/entry/common.c:82
> > entry_SYSCALL_64_after_hwframe+0x44/0xae
> > =====================================================
> > Kernel panic - not syncing: panic_on_kmsan set ...
> > CPU: 0 PID: 15049 Comm: syz-executor.0 Tainted: G B 5.15.0-rc2-syzkaller #0
> > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
> > Call Trace:
> > __dump_stack lib/dump_stack.c:88 [inline]
> > dump_stack_lvl+0x1ff/0x28e lib/dump_stack.c:106
> > dump_stack+0x25/0x28 lib/dump_stack.c:113
> > panic+0x44f/0xdeb kernel/panic.c:232
> > kmsan_report+0x2ee/0x300 mm/kmsan/report.c:186
> > __msan_warning+0xd7/0x150 mm/kmsan/instrumentation.c:208
> > __mpol_equal+0x567/0x590 mm/mempolicy.c:2260
> > mpol_equal include/linux/mempolicy.h:105 [inline]
> > vma_merge+0x4a1/0x1e60 mm/mmap.c:1190
> > mbind_range+0xcc8/0x1e80 mm/mempolicy.c:811
> > do_mbind+0xf42/0x15f0 mm/mempolicy.c:1333
> > kernel_mbind mm/mempolicy.c:1483 [inline]
> > __do_sys_mbind mm/mempolicy.c:1490 [inline]
> > __se_sys_mbind+0x437/0xb80 mm/mempolicy.c:1486
> > __x64_sys_mbind+0x19d/0x200 mm/mempolicy.c:1486
> > do_syscall_x64 arch/x86/entry/common.c:51 [inline]
> > do_syscall_64+0x54/0xd0 arch/x86/entry/common.c:82
> > entry_SYSCALL_64_after_hwframe+0x44/0xae
> > RIP: 0033:0x7f4a41b2c709
> > Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 bc ff ff ff f7 d8 64 89 01 48
> > RSP: 002b:00007f4a3f0a3188 EFLAGS: 00000246 ORIG_RAX: 00000000000000ed
> > RAX: ffffffffffffffda RBX: 00007f4a41c30f60 RCX: 00007f4a41b2c709
> > RDX: 0000000000002001 RSI: 0000000000c00007 RDI: 0000000020012000
> > RBP: 00007f4a41b86cb4 R08: 0000000000000000 R09: 0000010000000002
> > R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
> > R13: 00007f4a42164b2f R14: 00007f4a3f0a3300 R15: 0000000000022000
> >
>
> Hi Eric,
>
> this crash seems like the bug report [1] on Syzbot dashboard.
>
> [1] https://syzkaller.appspot.com/bug?id=028833194204bb15c2c43d822b8f7401360d57f5
>
> If yes, maybe you can push a patch testing request.
>
No, it was a different syzbot report, currently held in our queue.
(Andrew Morton has access to our internal bug, I CC him (b/201266830))
I can release it, at the expense of more noise to various mailing
lists, but really the bug is trivial.
On Fri, Oct 01, 2021 at 10:49:47AM -0700, Eric Dumazet wrote:
> From: Eric Dumazet <[email protected]>
>
> syzbot reported access to unitialized memory in mbind() [1]
>
> Issue came with commit bda420b98505 ("numa balancing: migrate on
> fault among multiple bound nodes")
>
> This commit added a new bit in MPOL_MODE_FLAGS, but only checked
> valid combination (MPOL_F_NUMA_BALANCING can only be used with MPOL_BIND)
> in do_set_mempolicy()
>
> This patch moves the check in sanitize_mpol_flags() so that it
> is also used by mbind()
>
> [1]
> BUG: KMSAN: uninit-value in __mpol_equal+0x567/0x590 mm/mempolicy.c:2260
> __mpol_equal+0x567/0x590 mm/mempolicy.c:2260
> mpol_equal include/linux/mempolicy.h:105 [inline]
> vma_merge+0x4a1/0x1e60 mm/mmap.c:1190
> mbind_range+0xcc8/0x1e80 mm/mempolicy.c:811
> do_mbind+0xf42/0x15f0 mm/mempolicy.c:1333
> kernel_mbind mm/mempolicy.c:1483 [inline]
> __do_sys_mbind mm/mempolicy.c:1490 [inline]
> __se_sys_mbind+0x437/0xb80 mm/mempolicy.c:1486
> __x64_sys_mbind+0x19d/0x200 mm/mempolicy.c:1486
> do_syscall_x64 arch/x86/entry/common.c:51 [inline]
> do_syscall_64+0x54/0xd0 arch/x86/entry/common.c:82
> entry_SYSCALL_64_after_hwframe+0x44/0xae
>
> Uninit was created at:
> slab_alloc_node mm/slub.c:3221 [inline]
> slab_alloc mm/slub.c:3230 [inline]
> kmem_cache_alloc+0x751/0xff0 mm/slub.c:3235
> mpol_new mm/mempolicy.c:293 [inline]
> do_mbind+0x912/0x15f0 mm/mempolicy.c:1289
> kernel_mbind mm/mempolicy.c:1483 [inline]
> __do_sys_mbind mm/mempolicy.c:1490 [inline]
> __se_sys_mbind+0x437/0xb80 mm/mempolicy.c:1486
> __x64_sys_mbind+0x19d/0x200 mm/mempolicy.c:1486
> do_syscall_x64 arch/x86/entry/common.c:51 [inline]
> do_syscall_64+0x54/0xd0 arch/x86/entry/common.c:82
> entry_SYSCALL_64_after_hwframe+0x44/0xae
> =====================================================
> Kernel panic - not syncing: panic_on_kmsan set ...
> CPU: 0 PID: 15049 Comm: syz-executor.0 Tainted: G B 5.15.0-rc2-syzkaller #0
> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
> Call Trace:
> __dump_stack lib/dump_stack.c:88 [inline]
> dump_stack_lvl+0x1ff/0x28e lib/dump_stack.c:106
> dump_stack+0x25/0x28 lib/dump_stack.c:113
> panic+0x44f/0xdeb kernel/panic.c:232
> kmsan_report+0x2ee/0x300 mm/kmsan/report.c:186
> __msan_warning+0xd7/0x150 mm/kmsan/instrumentation.c:208
> __mpol_equal+0x567/0x590 mm/mempolicy.c:2260
> mpol_equal include/linux/mempolicy.h:105 [inline]
> vma_merge+0x4a1/0x1e60 mm/mmap.c:1190
> mbind_range+0xcc8/0x1e80 mm/mempolicy.c:811
> do_mbind+0xf42/0x15f0 mm/mempolicy.c:1333
> kernel_mbind mm/mempolicy.c:1483 [inline]
> __do_sys_mbind mm/mempolicy.c:1490 [inline]
> __se_sys_mbind+0x437/0xb80 mm/mempolicy.c:1486
> __x64_sys_mbind+0x19d/0x200 mm/mempolicy.c:1486
> do_syscall_x64 arch/x86/entry/common.c:51 [inline]
> do_syscall_64+0x54/0xd0 arch/x86/entry/common.c:82
> entry_SYSCALL_64_after_hwframe+0x44/0xae
> RIP: 0033:0x7f4a41b2c709
> Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 bc ff ff ff f7 d8 64 89 01 48
> RSP: 002b:00007f4a3f0a3188 EFLAGS: 00000246 ORIG_RAX: 00000000000000ed
> RAX: ffffffffffffffda RBX: 00007f4a41c30f60 RCX: 00007f4a41b2c709
> RDX: 0000000000002001 RSI: 0000000000c00007 RDI: 0000000020012000
> RBP: 00007f4a41b86cb4 R08: 0000000000000000 R09: 0000010000000002
> R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
> R13: 00007f4a42164b2f R14: 00007f4a3f0a3300 R15: 0000000000022000
>
> Fixes: bda420b98505 ("numa balancing: migrate on fault among multiple bound nodes")
> Signed-off-by: Eric Dumazet <[email protected]>
> Reported-by: syzbot <[email protected]>
> Cc: "Huang, Ying" <[email protected]>
> Cc: Mel Gorman <[email protected]>
Acked-by: Mel Gorman <[email protected]>
--
Mel Gorman
SUSE Labs