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: [email protected] > > Closes: https://syzkaller.appspot.com/bug?extid=549710bad9c798e25b15 > > Fixes: cb6fc943b650 ("bcachefs: kill kvpmalloc()") > > Signed-off-by: I Hsin Cheng <[email protected]> > > --- > > 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/[email protected]/T/#m748384a36239a7f66e63cfde949e3db6bf14d5c6 > > > > syzbot reply me with: > > Hello, > > > > syzbot has tested the proposed patch and the reproducer did not trigger any > > issue: > > > > Reported-by: [email protected] > > Tested-by: [email protected] > > > > 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 > >
