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| author | Haotian Zhang <vulab@iscas.ac.cn> | 2026-07-11 22:21:55 +0800 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2026-09-07 17:18:23 +0200 |
| commit | 24a952786a5fb317e2cb1c057cd354546e7f5f33 (patch) | |
| tree | 01e02df0079973d6d18464dd6a9b197426140e2a | |
| parent | c3f211b7a277dd404b4e7d23095be964b5b46a27 (diff) | |
| download | linux-stable-24a952786a5fb317e2cb1c057cd354546e7f5f33.tar.gz linux-stable-24a952786a5fb317e2cb1c057cd354546e7f5f33.zip | |
dm-switch: use WRITE_ONCE() in switch_region_table_write()
commit c7391ebe33162c7962b313caea4d8e6b0bc2a671 upstream.
switch_region_table_read() accesses the region table with READ_ONCE()
and is called from the lockless switch_map() IO path. However,
switch_region_table_write() stores to the same array with a plain
assignment. This results in an inconsistent access pattern for a
lockless shared variable and may trigger data race reports.
Use WRITE_ONCE() to pair with the existing READ_ONCE() in
switch_region_table_read().
Cc: stable@vger.kernel.org
Fixes: 99eb1908e643 ("dm switch: factor out switch_region_table_read")
Signed-off-by: Haotian Zhang <vulab@iscas.ac.cn>
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | drivers/md/dm-switch.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/md/dm-switch.c b/drivers/md/dm-switch.c index dfd9fb52a6f3..50e1c7211c37 100644 --- a/drivers/md/dm-switch.c +++ b/drivers/md/dm-switch.c @@ -184,7 +184,7 @@ static void switch_region_table_write(struct switch_ctx *sctx, unsigned long reg pte = sctx->region_table[region_index]; pte &= ~((((region_table_slot_t)1 << sctx->region_table_entry_bits) - 1) << bit); pte |= (region_table_slot_t)value << bit; - sctx->region_table[region_index] = pte; + WRITE_ONCE(sctx->region_table[region_index], pte); } /* |