From: Zhang Yi yi.zhang@huawei.com
[ Upstream commit 02c7f7219ac0e2277b3379a3a0e9841ef464b6d4 ]
In a filesystem with a block size larger than 4KB, the hole length calculation for a non-extent inode in ext4_ind_map_blocks() can easily exceed INT_MAX. Then it could return a zero length hole and trigger the following waring and infinite in the iomap infrastructure.
------------[ cut here ]------------ WARNING: CPU: 3 PID: 434101 at fs/iomap/iter.c:34 iomap_iter_done+0x148/0x190 CPU: 3 UID: 0 PID: 434101 Comm: fsstress Not tainted 6.16.0-rc7+ #128 PREEMPT(voluntary) Hardware name: QEMU KVM Virtual Machine, BIOS unknown 2/2/2022 pstate: 60400005 (nZCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--) pc : iomap_iter_done+0x148/0x190 lr : iomap_iter+0x174/0x230 sp : ffff8000880af740 x29: ffff8000880af740 x28: ffff0000db8e6840 x27: 0000000000000000 x26: 0000000000000000 x25: ffff8000880af830 x24: 0000004000000000 x23: 0000000000000002 x22: 000001bfdbfa8000 x21: ffffa6a41c002e48 x20: 0000000000000001 x19: ffff8000880af808 x18: 0000000000000000 x17: 0000000000000000 x16: ffffa6a495ee6cd0 x15: 0000000000000000 x14: 00000000000003d4 x13: 00000000fa83b2da x12: 0000b236fc95f18c x11: ffffa6a4978b9c08 x10: 0000000000001da0 x9 : ffffa6a41c1a2a44 x8 : ffff8000880af5c8 x7 : 0000000001000000 x6 : 0000000000000000 x5 : 0000000000000004 x4 : 000001bfdbfa8000 x3 : 0000000000000000 x2 : 0000000000000000 x1 : 0000004004030000 x0 : 0000000000000000 Call trace: iomap_iter_done+0x148/0x190 (P) iomap_iter+0x174/0x230 iomap_fiemap+0x154/0x1d8 ext4_fiemap+0x110/0x140 [ext4] do_vfs_ioctl+0x4b8/0xbc0 __arm64_sys_ioctl+0x8c/0x120 invoke_syscall+0x6c/0x100 el0_svc_common.constprop.0+0x48/0xf0 do_el0_svc+0x24/0x38 el0_svc+0x38/0x120 el0t_64_sync_handler+0x10c/0x138 el0t_64_sync+0x198/0x1a0 ---[ end trace 0000000000000000 ]---
Cc: stable@kernel.org Fixes: facab4d9711e ("ext4: return hole from ext4_map_blocks()") Reported-by: Qu Wenruo wqu@suse.com Closes: https://lore.kernel.org/linux-ext4/9b650a52-9672-4604-a765-bb6be55d1e4a@gmx.... Tested-by: Qu Wenruo wqu@suse.com Signed-off-by: Zhang Yi yi.zhang@huawei.com Link: https://patch.msgid.link/20250811064532.1788289-1-yi.zhang@huaweicloud.com Signed-off-by: Theodore Ts'o tytso@mit.edu Signed-off-by: Sasha Levin sashal@kernel.org --- fs/ext4/indirect.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/fs/ext4/indirect.c b/fs/ext4/indirect.c index c2bb2ff3fbb6..48b368f13d30 100644 --- a/fs/ext4/indirect.c +++ b/fs/ext4/indirect.c @@ -537,7 +537,7 @@ int ext4_ind_map_blocks(handle_t *handle, struct inode *inode, int indirect_blks; int blocks_to_boundary = 0; int depth; - int count = 0; + u64 count = 0; ext4_fsblk_t first_block = 0;
trace_ext4_ind_map_blocks_enter(inode, map->m_lblk, map->m_len, flags); @@ -586,7 +586,7 @@ int ext4_ind_map_blocks(handle_t *handle, struct inode *inode, count++; /* Fill in size of a hole we found */ map->m_pblk = 0; - map->m_len = min_t(unsigned int, map->m_len, count); + map->m_len = umin(map->m_len, count); goto cleanup; }