The patch below does not apply to the 5.10-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.10.y git checkout FETCH_HEAD git cherry-pick -x 77de19b6867f2740cdcb6c9c7e50d522b47847a4 # <resolve conflicts, build, test, etc.> git commit -s git send-email --to 'stable@vger.kernel.org' --in-reply-to '2025082123-hemlock-starring-6459@gregkh' --subject-prefix 'PATCH 5.10.y' HEAD^..

Possible dependencies:

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 77de19b6867f2740cdcb6c9c7e50d522b47847a4 Mon Sep 17 00:00:00 2001 From: Chao Yu chao@kernel.org Date: Thu, 17 Jul 2025 21:26:33 +0800 Subject: [PATCH] f2fs: fix to avoid out-of-boundary access in dnode page

As Jiaming Zhang reported:

<TASK> __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x1c1/0x2a0 lib/dump_stack.c:120 print_address_description mm/kasan/report.c:378 [inline] print_report+0x17e/0x800 mm/kasan/report.c:480 kasan_report+0x147/0x180 mm/kasan/report.c:593 data_blkaddr fs/f2fs/f2fs.h:3053 [inline] f2fs_data_blkaddr fs/f2fs/f2fs.h:3058 [inline] f2fs_get_dnode_of_data+0x1a09/0x1c40 fs/f2fs/node.c:855 f2fs_reserve_block+0x53/0x310 fs/f2fs/data.c:1195 prepare_write_begin fs/f2fs/data.c:3395 [inline] f2fs_write_begin+0xf39/0x2190 fs/f2fs/data.c:3594 generic_perform_write+0x2c7/0x910 mm/filemap.c:4112 f2fs_buffered_write_iter fs/f2fs/file.c:4988 [inline] f2fs_file_write_iter+0x1ec8/0x2410 fs/f2fs/file.c:5216 new_sync_write fs/read_write.c:593 [inline] vfs_write+0x546/0xa90 fs/read_write.c:686 ksys_write+0x149/0x250 fs/read_write.c:738 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xf3/0x3d0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f

The root cause is in the corrupted image, there is a dnode has the same node id w/ its inode, so during f2fs_get_dnode_of_data(), it tries to access block address in dnode at offset 934, however it parses the dnode as inode node, so that get_dnode_addr() returns 360, then it tries to access page address from 360 + 934 * 4 = 4096 w/ 4 bytes.

To fix this issue, let's add sanity check for node id of all direct nodes during f2fs_get_dnode_of_data().

Cc: stable@kernel.org Reported-by: Jiaming Zhang r772577952@gmail.com Closes: https://groups.google.com/g/syzkaller/c/-ZnaaOOfO3M Signed-off-by: Chao Yu chao@kernel.org Signed-off-by: Jaegeuk Kim jaegeuk@kernel.org

diff --git a/fs/f2fs/node.c b/fs/f2fs/node.c index 4b3d9070e299..76aba1961b54 100644 --- a/fs/f2fs/node.c +++ b/fs/f2fs/node.c @@ -815,6 +815,16 @@ int f2fs_get_dnode_of_data(struct dnode_of_data *dn, pgoff_t index, int mode) for (i = 1; i <= level; i++) { bool done = false;

+ if (nids[i] && nids[i] == dn->inode->i_ino) { + err = -EFSCORRUPTED; + f2fs_err_ratelimited(sbi, + "inode mapping table is corrupted, run fsck to fix it, " + "ino:%lu, nid:%u, level:%d, offset:%d", + dn->inode->i_ino, nids[i], level, offset[level]); + set_sbi_flag(sbi, SBI_NEED_FSCK); + goto release_pages; + } + if (!nids[i] && mode == ALLOC_NODE) { /* alloc new node */ if (!f2fs_alloc_nid(sbi, &(nids[i]))) {