2.8 KiB
CVE-2024-38598
Description
In the Linux kernel, the following vulnerability has been resolved:md: fix resync softlockup when bitmap size is less than array sizeIs is reported that for dm-raid10, lvextend + lvchange --syncaction willtrigger following softlockup:kernel:watchdog: BUG: soft lockup - CPU#3 stuck for 26s! [mdX_resync:6976]CPU: 7 PID: 3588 Comm: mdX_resync Kdump: loaded Not tainted 6.9.0-rc4-next-20240419 #1RIP: 0010:_raw_spin_unlock_irq+0x13/0x30Call Trace: md_bitmap_start_sync+0x6b/0xf0 raid10_sync_request+0x25c/0x1b40 [raid10] md_do_sync+0x64b/0x1020 md_thread+0xa7/0x170 kthread+0xcf/0x100 ret_from_fork+0x30/0x50 ret_from_fork_asm+0x1a/0x30And the detailed process is as follows:md_do_sync j = mddev->resync_min while (j < max_sectors) sectors = raid10_sync_request(mddev, j, &skipped) if (!md_bitmap_start_sync(..., &sync_blocks)) // md_bitmap_start_sync set sync_blocks to 0 return sync_blocks + sectors_skippe; // sectors = 0; j += sectors; // j never changeRoot cause is that commit 301867b1c168 ("md/raid10: checkslab-out-of-bounds in md_bitmap_get_counter") return early frommd_bitmap_get_counter(), without setting returned blocks.Fix this problem by always set returned blocks frommd_bitmap_get_counter"(), as it used to be.Noted that this patch just fix the softlockup problem in kernel, thecase that bitmap size doesn't match array size still need to be fixed.
POC
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