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[PATCH] bcachefs: Fix unit-value within btree_bounce_alloc()

I Hsin Cheng posted 1 patch 7 months, 4 weeks ago 
fs/bcachefs/btree_io.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
[PATCH] bcachefs: Fix unit-value within btree_bounce_alloc()
Posted by I Hsin Cheng 7 months, 4 weeks ago 
Use "kvzalloc()" instead of "kvmalloc()" in btree_bounce_alloc() to
prevent uninit-value issue.

Reported-by: syzbot+549710bad9c798e25b15@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=549710bad9c798e25b15
Fixes: cb6fc943b650 ("bcachefs: kill kvpmalloc()")
Signed-off-by: I Hsin Cheng <richard120310@gmail.com>
---
syzbot reported an uninit-value issue. [1]

Though the uninit value was detected in the context of crc32_body(), the
memory was actually allocated in "btree_bounce_alloc()". Use
"kvzalloc()" to allocate the memory can solve the issue, and I've tested
against syzbot. [2]

If there're any further tests needed to be performed, please let me
know. I'll be more than happy to assist you with that, thanks !

[1]:
BUG: KMSAN: uninit-value in crc32_body lib/crc32.c:110 [inline]
BUG: KMSAN: uninit-value in crc32_le_generic lib/crc32.c:179 [inline]
BUG: KMSAN: uninit-value in __crc32c_le_base+0x43c/0xd80 lib/crc32.c:201
 crc32_body lib/crc32.c:110 [inline]
 crc32_le_generic lib/crc32.c:179 [inline]
 __crc32c_le_base+0x43c/0xd80 lib/crc32.c:201
 chksum_update+0x5b/0xd0 crypto/crc32c_generic.c:88
 crypto_shash_update+0x79/0xa0 crypto/shash.c:52
 crc32c+0xba/0x170 lib/libcrc32c.c:47
 bch2_checksum_update+0x106/0x1d0 fs/bcachefs/checksum.c:83
 bch2_checksum+0x3c5/0x7c0 fs/bcachefs/checksum.c:216
 __bch2_btree_node_write+0x528c/0x67c0 fs/bcachefs/btree_io.c:2151
 bch2_btree_node_write+0xa5/0x2e0 fs/bcachefs/btree_io.c:2288
 btree_node_write_if_need fs/bcachefs/btree_io.h:153 [inline]
 __btree_node_flush+0x4d0/0x640 fs/bcachefs/btree_trans_commit.c:229
 bch2_btree_node_flush0+0x35/0x60 fs/bcachefs/btree_trans_commit.c:238
 journal_flush_pins+0xce6/0x1780 fs/bcachefs/journal_reclaim.c:553
 __bch2_journal_reclaim+0xd88/0x1610 fs/bcachefs/journal_reclaim.c:685
 bch2_journal_reclaim_thread+0x18e/0x760 fs/bcachefs/journal_reclaim.c:727
 kthread+0x3e2/0x540 kernel/kthread.c:389
 ret_from_fork+0x6d/0x90 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244

Uninit was stored to memory at:
 memcpy_u64s_small fs/bcachefs/util.h:511 [inline]
 bkey_p_copy fs/bcachefs/bkey.h:46 [inline]
 bch2_sort_keys+0x1b4d/0x2cb0 fs/bcachefs/bkey_sort.c:194
 __bch2_btree_node_write+0x3acd/0x67c0 fs/bcachefs/btree_io.c:2100
 bch2_btree_node_write+0xa5/0x2e0 fs/bcachefs/btree_io.c:2288
 btree_node_write_if_need fs/bcachefs/btree_io.h:153 [inline]
 __btree_node_flush+0x4d0/0x640 fs/bcachefs/btree_trans_commit.c:229
 bch2_btree_node_flush0+0x35/0x60 fs/bcachefs/btree_trans_commit.c:238
 journal_flush_pins+0xce6/0x1780 fs/bcachefs/journal_reclaim.c:553
 __bch2_journal_reclaim+0xd88/0x1610 fs/bcachefs/journal_reclaim.c:685
 bch2_journal_reclaim_thread+0x18e/0x760 fs/bcachefs/journal_reclaim.c:727
 kthread+0x3e2/0x540 kernel/kthread.c:389
 ret_from_fork+0x6d/0x90 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244

Uninit was created at:
 __kmalloc_large_node+0x231/0x370 mm/slub.c:3994
 __do_kmalloc_node mm/slub.c:4027 [inline]
 __kmalloc_node+0xb10/0x10c0 mm/slub.c:4046
 kmalloc_node include/linux/slab.h:648 [inline]
 kvmalloc_node+0xc0/0x2d0 mm/util.c:634
 kvmalloc include/linux/slab.h:766 [inline]
 btree_bounce_alloc fs/bcachefs/btree_io.c:118 [inline]
 bch2_btree_node_read_done+0x4e68/0x75e0 fs/bcachefs/btree_io.c:1185
 btree_node_read_work+0x8a5/0x1eb0 fs/bcachefs/btree_io.c:1324
 bch2_btree_node_read+0x3d42/0x4b50
 __bch2_btree_root_read fs/bcachefs/btree_io.c:1748 [inline]
 bch2_btree_root_read+0xa6c/0x13d0 fs/bcachefs/btree_io.c:1772
 read_btree_roots+0x454/0xee0 fs/bcachefs/recovery.c:457
 bch2_fs_recovery+0x7b6a/0x93e0 fs/bcachefs/recovery.c:785
 bch2_fs_start+0x7b2/0xbd0 fs/bcachefs/super.c:1043
 bch2_fs_open+0x152a/0x15f0 fs/bcachefs/super.c:2105
 bch2_mount+0x90d/0x1d90 fs/bcachefs/fs.c:1906
 legacy_get_tree+0x114/0x290 fs/fs_context.c:662
 vfs_get_tree+0xa7/0x570 fs/super.c:1779
 do_new_mount+0x71f/0x15e0 fs/namespace.c:3352
 path_mount+0x742/0x1f20 fs/namespace.c:3679
 do_mount fs/namespace.c:3692 [inline]
 __do_sys_mount fs/namespace.c:3898 [inline]
 __se_sys_mount+0x725/0x810 fs/namespace.c:3875
 __x64_sys_mount+0xe4/0x150 fs/namespace.c:3875
 x64_sys_call+0x2bf4/0x3b50 arch/x86/include/generated/asm/syscalls_64.h:166
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xcf/0x1e0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

[2]:
https://lore.kernel.org/all/000000000000736bd406151001d7@google.com/T/#m748384a36239a7f66e63cfde949e3db6bf14d5c6

syzbot reply me with:
Hello,

syzbot has tested the proposed patch and the reproducer did not trigger any issue:

Reported-by: syzbot+549710bad9c798e25b15@syzkaller.appspotmail.com
Tested-by: syzbot+549710bad9c798e25b15@syzkaller.appspotmail.com

Tested on:

commit:         614da38e Merge tag 'hid-for-linus-2024051401' of git:/..
git tree:       git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
console output: https://syzkaller.appspot.com/x/log.txt?x=10be763f980000
kernel config:  https://syzkaller.appspot.com/x/.config?x=49342144b6a907af
dashboard link: https://syzkaller.appspot.com/bug?extid=549710bad9c798e25b15
compiler:       Debian clang version 15.0.6, Debian LLD 15.0.6
patch:          https://syzkaller.appspot.com/x/patch.diff?x=15b99a6f980000

Note: testing is done by a robot and is best-effort only.

Best regards,
I Hsin Cheng
---
 fs/bcachefs/btree_io.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/bcachefs/btree_io.c b/fs/bcachefs/btree_io.c
index debb0edc3455..dc00c5273ffe 100644
--- a/fs/bcachefs/btree_io.c
+++ b/fs/bcachefs/btree_io.c
@@ -115,7 +115,7 @@ static void *btree_bounce_alloc(struct bch_fs *c, size_t size,
 	BUG_ON(size > c->opts.btree_node_size);
 
 	*used_mempool = false;
-	p = kvmalloc(size, __GFP_NOWARN|GFP_NOWAIT);
+	p = kvzalloc(size, __GFP_NOWARN|GFP_NOWAIT);
 	if (!p) {
 		*used_mempool = true;
 		p = mempool_alloc(&c->btree_bounce_pool, GFP_NOFS);
-- 
2.43.0
Re: [PATCH] bcachefs: Fix unit-value within btree_bounce_alloc()
Posted by Kent Overstreet 7 months, 4 weeks ago 
On Thu, Apr 24, 2025 at 12:37:18AM +0800, I Hsin Cheng wrote:
> Use "kvzalloc()" instead of "kvmalloc()" in btree_bounce_alloc() to
> prevent uninit-value issue.
> 
> Reported-by: syzbot+549710bad9c798e25b15@syzkaller.appspotmail.com
> Closes: https://syzkaller.appspot.com/bug?extid=549710bad9c798e25b15
> Fixes: cb6fc943b650 ("bcachefs: kill kvpmalloc()")
> Signed-off-by: I Hsin Cheng <richard120310@gmail.com>
> ---
> syzbot reported an uninit-value issue. [1]
> 
> Though the uninit value was detected in the context of crc32_body(), the
> memory was actually allocated in "btree_bounce_alloc()". Use
> "kvzalloc()" to allocate the memory can solve the issue, and I've tested
> against syzbot. [2]
> 
> If there're any further tests needed to be performed, please let me
> know. I'll be more than happy to assist you with that, thanks !

See Documentation/filesystems/bcachefs/SubmittingPatches.

And this isn't the correct fix - the correct fix is already in Linus's
tree.

> 
> [1]:
> BUG: KMSAN: uninit-value in crc32_body lib/crc32.c:110 [inline]
> BUG: KMSAN: uninit-value in crc32_le_generic lib/crc32.c:179 [inline]
> BUG: KMSAN: uninit-value in __crc32c_le_base+0x43c/0xd80 lib/crc32.c:201
>  crc32_body lib/crc32.c:110 [inline]
>  crc32_le_generic lib/crc32.c:179 [inline]
>  __crc32c_le_base+0x43c/0xd80 lib/crc32.c:201
>  chksum_update+0x5b/0xd0 crypto/crc32c_generic.c:88
>  crypto_shash_update+0x79/0xa0 crypto/shash.c:52
>  crc32c+0xba/0x170 lib/libcrc32c.c:47
>  bch2_checksum_update+0x106/0x1d0 fs/bcachefs/checksum.c:83
>  bch2_checksum+0x3c5/0x7c0 fs/bcachefs/checksum.c:216
>  __bch2_btree_node_write+0x528c/0x67c0 fs/bcachefs/btree_io.c:2151
>  bch2_btree_node_write+0xa5/0x2e0 fs/bcachefs/btree_io.c:2288
>  btree_node_write_if_need fs/bcachefs/btree_io.h:153 [inline]
>  __btree_node_flush+0x4d0/0x640 fs/bcachefs/btree_trans_commit.c:229
>  bch2_btree_node_flush0+0x35/0x60 fs/bcachefs/btree_trans_commit.c:238
>  journal_flush_pins+0xce6/0x1780 fs/bcachefs/journal_reclaim.c:553
>  __bch2_journal_reclaim+0xd88/0x1610 fs/bcachefs/journal_reclaim.c:685
>  bch2_journal_reclaim_thread+0x18e/0x760 fs/bcachefs/journal_reclaim.c:727
>  kthread+0x3e2/0x540 kernel/kthread.c:389
>  ret_from_fork+0x6d/0x90 arch/x86/kernel/process.c:147
>  ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
> 
> Uninit was stored to memory at:
>  memcpy_u64s_small fs/bcachefs/util.h:511 [inline]
>  bkey_p_copy fs/bcachefs/bkey.h:46 [inline]
>  bch2_sort_keys+0x1b4d/0x2cb0 fs/bcachefs/bkey_sort.c:194
>  __bch2_btree_node_write+0x3acd/0x67c0 fs/bcachefs/btree_io.c:2100
>  bch2_btree_node_write+0xa5/0x2e0 fs/bcachefs/btree_io.c:2288
>  btree_node_write_if_need fs/bcachefs/btree_io.h:153 [inline]
>  __btree_node_flush+0x4d0/0x640 fs/bcachefs/btree_trans_commit.c:229
>  bch2_btree_node_flush0+0x35/0x60 fs/bcachefs/btree_trans_commit.c:238
>  journal_flush_pins+0xce6/0x1780 fs/bcachefs/journal_reclaim.c:553
>  __bch2_journal_reclaim+0xd88/0x1610 fs/bcachefs/journal_reclaim.c:685
>  bch2_journal_reclaim_thread+0x18e/0x760 fs/bcachefs/journal_reclaim.c:727
>  kthread+0x3e2/0x540 kernel/kthread.c:389
>  ret_from_fork+0x6d/0x90 arch/x86/kernel/process.c:147
>  ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
> 
> Uninit was created at:
>  __kmalloc_large_node+0x231/0x370 mm/slub.c:3994
>  __do_kmalloc_node mm/slub.c:4027 [inline]
>  __kmalloc_node+0xb10/0x10c0 mm/slub.c:4046
>  kmalloc_node include/linux/slab.h:648 [inline]
>  kvmalloc_node+0xc0/0x2d0 mm/util.c:634
>  kvmalloc include/linux/slab.h:766 [inline]
>  btree_bounce_alloc fs/bcachefs/btree_io.c:118 [inline]
>  bch2_btree_node_read_done+0x4e68/0x75e0 fs/bcachefs/btree_io.c:1185
>  btree_node_read_work+0x8a5/0x1eb0 fs/bcachefs/btree_io.c:1324
>  bch2_btree_node_read+0x3d42/0x4b50
>  __bch2_btree_root_read fs/bcachefs/btree_io.c:1748 [inline]
>  bch2_btree_root_read+0xa6c/0x13d0 fs/bcachefs/btree_io.c:1772
>  read_btree_roots+0x454/0xee0 fs/bcachefs/recovery.c:457
>  bch2_fs_recovery+0x7b6a/0x93e0 fs/bcachefs/recovery.c:785
>  bch2_fs_start+0x7b2/0xbd0 fs/bcachefs/super.c:1043
>  bch2_fs_open+0x152a/0x15f0 fs/bcachefs/super.c:2105
>  bch2_mount+0x90d/0x1d90 fs/bcachefs/fs.c:1906
>  legacy_get_tree+0x114/0x290 fs/fs_context.c:662
>  vfs_get_tree+0xa7/0x570 fs/super.c:1779
>  do_new_mount+0x71f/0x15e0 fs/namespace.c:3352
>  path_mount+0x742/0x1f20 fs/namespace.c:3679
>  do_mount fs/namespace.c:3692 [inline]
>  __do_sys_mount fs/namespace.c:3898 [inline]
>  __se_sys_mount+0x725/0x810 fs/namespace.c:3875
>  __x64_sys_mount+0xe4/0x150 fs/namespace.c:3875
>  x64_sys_call+0x2bf4/0x3b50 arch/x86/include/generated/asm/syscalls_64.h:166
>  do_syscall_x64 arch/x86/entry/common.c:52 [inline]
>  do_syscall_64+0xcf/0x1e0 arch/x86/entry/common.c:83
>  entry_SYSCALL_64_after_hwframe+0x77/0x7f
> 
> [2]:
> https://lore.kernel.org/all/000000000000736bd406151001d7@google.com/T/#m748384a36239a7f66e63cfde949e3db6bf14d5c6
> 
> syzbot reply me with:
> Hello,
> 
> syzbot has tested the proposed patch and the reproducer did not trigger any issue:
> 
> Reported-by: syzbot+549710bad9c798e25b15@syzkaller.appspotmail.com
> Tested-by: syzbot+549710bad9c798e25b15@syzkaller.appspotmail.com
> 
> Tested on:
> 
> commit:         614da38e Merge tag 'hid-for-linus-2024051401' of git:/..
> git tree:       git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
> console output: https://syzkaller.appspot.com/x/log.txt?x=10be763f980000
> kernel config:  https://syzkaller.appspot.com/x/.config?x=49342144b6a907af
> dashboard link: https://syzkaller.appspot.com/bug?extid=549710bad9c798e25b15
> compiler:       Debian clang version 15.0.6, Debian LLD 15.0.6
> patch:          https://syzkaller.appspot.com/x/patch.diff?x=15b99a6f980000
> 
> Note: testing is done by a robot and is best-effort only.
> 
> Best regards,
> I Hsin Cheng
> ---
>  fs/bcachefs/btree_io.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/fs/bcachefs/btree_io.c b/fs/bcachefs/btree_io.c
> index debb0edc3455..dc00c5273ffe 100644
> --- a/fs/bcachefs/btree_io.c
> +++ b/fs/bcachefs/btree_io.c
> @@ -115,7 +115,7 @@ static void *btree_bounce_alloc(struct bch_fs *c, size_t size,
>  	BUG_ON(size > c->opts.btree_node_size);
>  
>  	*used_mempool = false;
> -	p = kvmalloc(size, __GFP_NOWARN|GFP_NOWAIT);
> +	p = kvzalloc(size, __GFP_NOWARN|GFP_NOWAIT);
>  	if (!p) {
>  		*used_mempool = true;
>  		p = mempool_alloc(&c->btree_bounce_pool, GFP_NOFS);
> -- 
> 2.43.0
>
Re: [PATCH] bcachefs: Fix unit-value within btree_bounce_alloc()
Posted by I Hsin Cheng 7 months, 3 weeks ago 
On Wed, Apr 23, 2025 at 12:45:20PM -0400, Kent Overstreet wrote:
> On Thu, Apr 24, 2025 at 12:37:18AM +0800, I Hsin Cheng wrote:
> > Use "kvzalloc()" instead of "kvmalloc()" in btree_bounce_alloc() to
> > prevent uninit-value issue.
> > 
> > Reported-by: syzbot+549710bad9c798e25b15@syzkaller.appspotmail.com
> > Closes: https://syzkaller.appspot.com/bug?extid=549710bad9c798e25b15
> > Fixes: cb6fc943b650 ("bcachefs: kill kvpmalloc()")
> > Signed-off-by: I Hsin Cheng <richard120310@gmail.com>
> > ---
> > syzbot reported an uninit-value issue. [1]
> > 
> > Though the uninit value was detected in the context of crc32_body(), the
> > memory was actually allocated in "btree_bounce_alloc()". Use
> > "kvzalloc()" to allocate the memory can solve the issue, and I've tested
> > against syzbot. [2]
> > 
> > If there're any further tests needed to be performed, please let me
> > know. I'll be more than happy to assist you with that, thanks !
> 
> See Documentation/filesystems/bcachefs/SubmittingPatches.
>

Sure ! Thanks for the info.

> And this isn't the correct fix - the correct fix is already in Linus's
> tree.

Ahh ok, may I ask for the commit hash or title so I can learn from it ?

Best regards,
I Hsin Cheng
> 
> > 
> > [1]:
> > BUG: KMSAN: uninit-value in crc32_body lib/crc32.c:110 [inline]
> > BUG: KMSAN: uninit-value in crc32_le_generic lib/crc32.c:179 [inline]
> > BUG: KMSAN: uninit-value in __crc32c_le_base+0x43c/0xd80 lib/crc32.c:201
> >  crc32_body lib/crc32.c:110 [inline]
> >  crc32_le_generic lib/crc32.c:179 [inline]
> >  __crc32c_le_base+0x43c/0xd80 lib/crc32.c:201
> >  chksum_update+0x5b/0xd0 crypto/crc32c_generic.c:88
> >  crypto_shash_update+0x79/0xa0 crypto/shash.c:52
> >  crc32c+0xba/0x170 lib/libcrc32c.c:47
> >  bch2_checksum_update+0x106/0x1d0 fs/bcachefs/checksum.c:83
> >  bch2_checksum+0x3c5/0x7c0 fs/bcachefs/checksum.c:216
> >  __bch2_btree_node_write+0x528c/0x67c0 fs/bcachefs/btree_io.c:2151
> >  bch2_btree_node_write+0xa5/0x2e0 fs/bcachefs/btree_io.c:2288
> >  btree_node_write_if_need fs/bcachefs/btree_io.h:153 [inline]
> >  __btree_node_flush+0x4d0/0x640 fs/bcachefs/btree_trans_commit.c:229
> >  bch2_btree_node_flush0+0x35/0x60 fs/bcachefs/btree_trans_commit.c:238
> >  journal_flush_pins+0xce6/0x1780 fs/bcachefs/journal_reclaim.c:553
> >  __bch2_journal_reclaim+0xd88/0x1610 fs/bcachefs/journal_reclaim.c:685
> >  bch2_journal_reclaim_thread+0x18e/0x760 fs/bcachefs/journal_reclaim.c:727
> >  kthread+0x3e2/0x540 kernel/kthread.c:389
> >  ret_from_fork+0x6d/0x90 arch/x86/kernel/process.c:147
> >  ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
> > 
> > Uninit was stored to memory at:
> >  memcpy_u64s_small fs/bcachefs/util.h:511 [inline]
> >  bkey_p_copy fs/bcachefs/bkey.h:46 [inline]
> >  bch2_sort_keys+0x1b4d/0x2cb0 fs/bcachefs/bkey_sort.c:194
> >  __bch2_btree_node_write+0x3acd/0x67c0 fs/bcachefs/btree_io.c:2100
> >  bch2_btree_node_write+0xa5/0x2e0 fs/bcachefs/btree_io.c:2288
> >  btree_node_write_if_need fs/bcachefs/btree_io.h:153 [inline]
> >  __btree_node_flush+0x4d0/0x640 fs/bcachefs/btree_trans_commit.c:229
> >  bch2_btree_node_flush0+0x35/0x60 fs/bcachefs/btree_trans_commit.c:238
> >  journal_flush_pins+0xce6/0x1780 fs/bcachefs/journal_reclaim.c:553
> >  __bch2_journal_reclaim+0xd88/0x1610 fs/bcachefs/journal_reclaim.c:685
> >  bch2_journal_reclaim_thread+0x18e/0x760 fs/bcachefs/journal_reclaim.c:727
> >  kthread+0x3e2/0x540 kernel/kthread.c:389
> >  ret_from_fork+0x6d/0x90 arch/x86/kernel/process.c:147
> >  ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
> > 
> > Uninit was created at:
> >  __kmalloc_large_node+0x231/0x370 mm/slub.c:3994
> >  __do_kmalloc_node mm/slub.c:4027 [inline]
> >  __kmalloc_node+0xb10/0x10c0 mm/slub.c:4046
> >  kmalloc_node include/linux/slab.h:648 [inline]
> >  kvmalloc_node+0xc0/0x2d0 mm/util.c:634
> >  kvmalloc include/linux/slab.h:766 [inline]
> >  btree_bounce_alloc fs/bcachefs/btree_io.c:118 [inline]
> >  bch2_btree_node_read_done+0x4e68/0x75e0 fs/bcachefs/btree_io.c:1185
> >  btree_node_read_work+0x8a5/0x1eb0 fs/bcachefs/btree_io.c:1324
> >  bch2_btree_node_read+0x3d42/0x4b50
> >  __bch2_btree_root_read fs/bcachefs/btree_io.c:1748 [inline]
> >  bch2_btree_root_read+0xa6c/0x13d0 fs/bcachefs/btree_io.c:1772
> >  read_btree_roots+0x454/0xee0 fs/bcachefs/recovery.c:457
> >  bch2_fs_recovery+0x7b6a/0x93e0 fs/bcachefs/recovery.c:785
> >  bch2_fs_start+0x7b2/0xbd0 fs/bcachefs/super.c:1043
> >  bch2_fs_open+0x152a/0x15f0 fs/bcachefs/super.c:2105
> >  bch2_mount+0x90d/0x1d90 fs/bcachefs/fs.c:1906
> >  legacy_get_tree+0x114/0x290 fs/fs_context.c:662
> >  vfs_get_tree+0xa7/0x570 fs/super.c:1779
> >  do_new_mount+0x71f/0x15e0 fs/namespace.c:3352
> >  path_mount+0x742/0x1f20 fs/namespace.c:3679
> >  do_mount fs/namespace.c:3692 [inline]
> >  __do_sys_mount fs/namespace.c:3898 [inline]
> >  __se_sys_mount+0x725/0x810 fs/namespace.c:3875
> >  __x64_sys_mount+0xe4/0x150 fs/namespace.c:3875
> >  x64_sys_call+0x2bf4/0x3b50 arch/x86/include/generated/asm/syscalls_64.h:166
> >  do_syscall_x64 arch/x86/entry/common.c:52 [inline]
> >  do_syscall_64+0xcf/0x1e0 arch/x86/entry/common.c:83
> >  entry_SYSCALL_64_after_hwframe+0x77/0x7f
> > 
> > [2]:
> > https://lore.kernel.org/all/000000000000736bd406151001d7@google.com/T/#m748384a36239a7f66e63cfde949e3db6bf14d5c6
> > 
> > syzbot reply me with:
> > Hello,
> > 
> > syzbot has tested the proposed patch and the reproducer did not trigger any issue:
> > 
> > Reported-by: syzbot+549710bad9c798e25b15@syzkaller.appspotmail.com
> > Tested-by: syzbot+549710bad9c798e25b15@syzkaller.appspotmail.com
> > 
> > Tested on:
> > 
> > commit:         614da38e Merge tag 'hid-for-linus-2024051401' of git:/..
> > git tree:       git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
> > console output: https://syzkaller.appspot.com/x/log.txt?x=10be763f980000
> > kernel config:  https://syzkaller.appspot.com/x/.config?x=49342144b6a907af
> > dashboard link: https://syzkaller.appspot.com/bug?extid=549710bad9c798e25b15
> > compiler:       Debian clang version 15.0.6, Debian LLD 15.0.6
> > patch:          https://syzkaller.appspot.com/x/patch.diff?x=15b99a6f980000
> > 
> > Note: testing is done by a robot and is best-effort only.
> > 
> > Best regards,
> > I Hsin Cheng
> > ---
> >  fs/bcachefs/btree_io.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> > 
> > diff --git a/fs/bcachefs/btree_io.c b/fs/bcachefs/btree_io.c
> > index debb0edc3455..dc00c5273ffe 100644
> > --- a/fs/bcachefs/btree_io.c
> > +++ b/fs/bcachefs/btree_io.c
> > @@ -115,7 +115,7 @@ static void *btree_bounce_alloc(struct bch_fs *c, size_t size,
> >  	BUG_ON(size > c->opts.btree_node_size);
> >  
> >  	*used_mempool = false;
> > -	p = kvmalloc(size, __GFP_NOWARN|GFP_NOWAIT);
> > +	p = kvzalloc(size, __GFP_NOWARN|GFP_NOWAIT);
> >  	if (!p) {
> >  		*used_mempool = true;
> >  		p = mempool_alloc(&c->btree_bounce_pool, GFP_NOFS);
> > -- 
> > 2.43.0
> >
Re: [PATCH] bcachefs: Fix unit-value within btree_bounce_alloc()
Posted by Kent Overstreet 7 months, 3 weeks ago 
On Sat, Apr 26, 2025 at 12:53:49AM +0800, I Hsin Cheng wrote:
> On Wed, Apr 23, 2025 at 12:45:20PM -0400, Kent Overstreet wrote:
> > On Thu, Apr 24, 2025 at 12:37:18AM +0800, I Hsin Cheng wrote:
> > > Use "kvzalloc()" instead of "kvmalloc()" in btree_bounce_alloc() to
> > > prevent uninit-value issue.
> > > 
> > > Reported-by: syzbot+549710bad9c798e25b15@syzkaller.appspotmail.com
> > > Closes: https://syzkaller.appspot.com/bug?extid=549710bad9c798e25b15
> > > Fixes: cb6fc943b650 ("bcachefs: kill kvpmalloc()")
> > > Signed-off-by: I Hsin Cheng <richard120310@gmail.com>
> > > ---
> > > syzbot reported an uninit-value issue. [1]
> > > 
> > > Though the uninit value was detected in the context of crc32_body(), the
> > > memory was actually allocated in "btree_bounce_alloc()". Use
> > > "kvzalloc()" to allocate the memory can solve the issue, and I've tested
> > > against syzbot. [2]
> > > 
> > > If there're any further tests needed to be performed, please let me
> > > know. I'll be more than happy to assist you with that, thanks !
> > 
> > See Documentation/filesystems/bcachefs/SubmittingPatches.
> >
> 
> Sure ! Thanks for the info.
> 
> > And this isn't the correct fix - the correct fix is already in Linus's
> > tree.
> 
> Ahh ok, may I ask for the commit hash or title so I can learn from it ?

9c3a2c9b471a bcachefs: Disable asm memcpys when kmsan enabled

Patchew 2.1-devel-b67e4c2

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