From 39c71357e68e2f03766f9321b9f4882e49ff1442 Mon Sep 17 00:00:00 2001 From: Billy Tsai Date: Mon, 23 Oct 2023 16:02:37 +0800 Subject: [PATCH] i3c: master: mipi-i3c-hci: Fix a kernel panic for accessing DAT_data. [ Upstream commit b53e9758a31c683fc8615df930262192ed5f034b ] The `i3c_master_bus_init` function may attach the I2C devices before the I3C bus initialization. In this flow, the DAT `alloc_entry`` will be used before the DAT `init`. Additionally, if the `i3c_master_bus_init` fails, the DAT `cleanup` will execute before the device is detached, which will execue DAT `free_entry` function. The above scenario can cause the driver to use DAT_data when it is NULL. Signed-off-by: Billy Tsai Link: https://lore.kernel.org/r/20231023080237.560936-1-billy_tsai@aspeedtech.com Signed-off-by: Alexandre Belloni Signed-off-by: Sasha Levin --- drivers/i3c/master/mipi-i3c-hci/dat_v1.c | 27 ++++++++++++++++-------- 1 file changed, 18 insertions(+), 9 deletions(-) diff --git a/drivers/i3c/master/mipi-i3c-hci/dat_v1.c b/drivers/i3c/master/mipi-i3c-hci/dat_v1.c index 97bb49ff5b53..47b9b4d4ed3f 100644 --- a/drivers/i3c/master/mipi-i3c-hci/dat_v1.c +++ b/drivers/i3c/master/mipi-i3c-hci/dat_v1.c @@ -64,15 +64,17 @@ static int hci_dat_v1_init(struct i3c_hci *hci) return -EOPNOTSUPP; } - /* use a bitmap for faster free slot search */ - hci->DAT_data = bitmap_zalloc(hci->DAT_entries, GFP_KERNEL); - if (!hci->DAT_data) - return -ENOMEM; + if (!hci->DAT_data) { + /* use a bitmap for faster free slot search */ + hci->DAT_data = bitmap_zalloc(hci->DAT_entries, GFP_KERNEL); + if (!hci->DAT_data) + return -ENOMEM; - /* clear them */ - for (dat_idx = 0; dat_idx < hci->DAT_entries; dat_idx++) { - dat_w0_write(dat_idx, 0); - dat_w1_write(dat_idx, 0); + /* clear them */ + for (dat_idx = 0; dat_idx < hci->DAT_entries; dat_idx++) { + dat_w0_write(dat_idx, 0); + dat_w1_write(dat_idx, 0); + } } return 0; @@ -87,7 +89,13 @@ static void hci_dat_v1_cleanup(struct i3c_hci *hci) static int hci_dat_v1_alloc_entry(struct i3c_hci *hci) { unsigned int dat_idx; + int ret; + if (!hci->DAT_data) { + ret = hci_dat_v1_init(hci); + if (ret) + return ret; + } dat_idx = find_first_zero_bit(hci->DAT_data, hci->DAT_entries); if (dat_idx >= hci->DAT_entries) return -ENOENT; @@ -103,7 +111,8 @@ static void hci_dat_v1_free_entry(struct i3c_hci *hci, unsigned int dat_idx) { dat_w0_write(dat_idx, 0); dat_w1_write(dat_idx, 0); - __clear_bit(dat_idx, hci->DAT_data); + if (hci->DAT_data) + __clear_bit(dat_idx, hci->DAT_data); } static void hci_dat_v1_set_dynamic_addr(struct i3c_hci *hci,