6.6-stable review patch. If anyone has any objections, please let me know.
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From: Mans Rullgard mans@mansr.com
[ Upstream commit 4756fa529b2f12b7cb8f21fe229b0f6f47190829 ]
If spi_sync() is called with the non-empty queue and the same spi_message is then reused, the complete callback for the message remains set while the context is cleared, leading to a null pointer dereference when the callback is invoked from spi_finalize_current_message().
With function inlining disabled, the call stack might look like this:
_raw_spin_lock_irqsave from complete_with_flags+0x18/0x58 complete_with_flags from spi_complete+0x8/0xc spi_complete from spi_finalize_current_message+0xec/0x184 spi_finalize_current_message from spi_transfer_one_message+0x2a8/0x474 spi_transfer_one_message from __spi_pump_transfer_message+0x104/0x230 __spi_pump_transfer_message from __spi_transfer_message_noqueue+0x30/0xc4 __spi_transfer_message_noqueue from __spi_sync+0x204/0x248 __spi_sync from spi_sync+0x24/0x3c spi_sync from mcp251xfd_regmap_crc_read+0x124/0x28c [mcp251xfd] mcp251xfd_regmap_crc_read [mcp251xfd] from _regmap_raw_read+0xf8/0x154 _regmap_raw_read from _regmap_bus_read+0x44/0x70 _regmap_bus_read from _regmap_read+0x60/0xd8 _regmap_read from regmap_read+0x3c/0x5c regmap_read from mcp251xfd_alloc_can_err_skb+0x1c/0x54 [mcp251xfd] mcp251xfd_alloc_can_err_skb [mcp251xfd] from mcp251xfd_irq+0x194/0xe70 [mcp251xfd] mcp251xfd_irq [mcp251xfd] from irq_thread_fn+0x1c/0x78 irq_thread_fn from irq_thread+0x118/0x1f4 irq_thread from kthread+0xd8/0xf4 kthread from ret_from_fork+0x14/0x28
Fix this by also setting message->complete to NULL when the transfer is complete.
Fixes: ae7d2346dc89 ("spi: Don't use the message queue if possible in spi_sync")
Signed-off-by: Mans Rullgard mans@mansr.com Link: https://lore.kernel.org/r/20240430182705.13019-1-mans@mansr.com Signed-off-by: Mark Brown broonie@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/spi/spi.c | 1 + 1 file changed, 1 insertion(+)
diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c index 1e08cd571d21a..76383ddbd6a6f 100644 --- a/drivers/spi/spi.c +++ b/drivers/spi/spi.c @@ -4261,6 +4261,7 @@ static int __spi_sync(struct spi_device *spi, struct spi_message *message) wait_for_completion(&done); status = message->status; } + message->complete = NULL; message->context = NULL;
return status;