| Message ID | 4269631780e5ba789cf1ae391eec1b959def7d99.1712761976.git.baruch@tkos.co.il |
|---|---|
| State | Superseded |
| Delegated to: | Wolfram Sang |
| Headers | show |
| Series | i2c: smbus: fix NULL function pointer dereference | expand |
Hi Baruch, > Callers of __i2c_transfer() must verify that master_xfer is not NULL. > Check that before i2c_smbus_xfer_emulated() call. Right, thank you very much for this report! I think we should have a more defensive solution, though. I'll send my idea next. If you could check it, that would be much appreciated. All the best, Wolfram
diff --git a/drivers/i2c/i2c-core-smbus.c b/drivers/i2c/i2c-core-smbus.c index e3b96fc53b5c..d252716c9f74 100644 --- a/drivers/i2c/i2c-core-smbus.c +++ b/drivers/i2c/i2c-core-smbus.c @@ -604,8 +604,11 @@ s32 __i2c_smbus_xfer(struct i2c_adapter *adapter, u16 addr, */ } - res = i2c_smbus_xfer_emulated(adapter, addr, flags, read_write, - command, protocol, data); + if (adapter->algo->master_xfer) + res = i2c_smbus_xfer_emulated(adapter, addr, flags, read_write, + command, protocol, data); + else + res = -EOPNOTSUPP; trace: /* If enabled, the reply tracepoint is conditional on read_write. */
Running i2cdetect on i2c slave device (i2c-designware) gives this splat: [ 53.306730] Unable to handle kernel NULL pointer dereference at virtual address 0000000000000000 [ 53.318340] Mem abort info: [ 53.323864] ESR = 0x0000000086000004 [ 53.330374] EC = 0x21: IABT (current EL), IL = 32 bits [ 53.338446] SET = 0, FnV = 0 [ 53.344263] EA = 0, S1PTW = 0 [ 53.350166] FSC = 0x04: level 0 translation fault [ 53.357806] user pgtable: 4k pages, 48-bit VAs, pgdp=00000008c7d8e000 [ 53.367008] [0000000000000000] pgd=0000000000000000, p4d=0000000000000000 [ 53.376559] Internal error: Oops: 0000000086000004 [#1] PREEMPT SMP [ 53.382892] Modules linked in: [ 53.385936] CPU: 6 PID: 420 Comm: i2cdetect Not tainted 6.9.0-rc3-yocto-standard+ #1295 [ 53.393926] Hardware name: xxx (DT) [ 53.398531] pstate: 60400009 (nZCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--) [ 53.405480] pc : 0x0 [ 53.407656] lr : __i2c_transfer+0x1f4/0x830 [ 53.411834] sp : ffff800082c13b00 [ 53.415136] x29: ffff800082c13b00 x28: 0000000000000001 x27: 0000000000000001 [ 53.422259] x26: ffff8000813aa340 x25: ffff0000c69553c0 x24: 00000000ffff0eeb [ 53.429383] x23: ffff8000813a6000 x22: ffff800082c13bc0 x21: 0000000000000000 [ 53.436506] x20: 0000000000000001 x19: ffff000040b82140 x18: 0000000000000000 [ 53.443630] x17: 0000000000000000 x16: 0000000000000000 x15: 0000ffffff59bd58 [ 53.450753] x14: 0000000000000000 x13: 0000000000000000 x12: 0000000000000000 [ 53.457876] x11: 0000000000000000 x10: 0000000000000000 x9 : ffff8000807e4470 [ 53.464999] x8 : ffff800082c13c05 x7 : 0000000000000001 x6 : ffff800082c13d56 [ 53.472122] x5 : 0000000000000001 x4 : 0000000000000000 x3 : 0000000000000000 [ 53.479245] x2 : 0000000000000001 x1 : ffff800082c13bc0 x0 : ffff000040b82140 [ 53.486368] Call trace: [ 53.488803] 0x0 [ 53.490629] i2c_smbus_xfer_emulated+0x148/0x6d0 [ 53.495236] __i2c_smbus_xfer+0x130/0x4d0 [ 53.499235] i2c_smbus_xfer+0xc0/0x128 [ 53.502973] i2cdev_ioctl_smbus+0x110/0x2b0 [ 53.507145] i2cdev_ioctl+0x9c/0x348 [ 53.510710] __arm64_sys_ioctl+0xb4/0xe0 [ 53.514624] invoke_syscall+0x4c/0x118 [ 53.518365] el0_svc_common.constprop.0+0xc4/0xf0 [ 53.523058] do_el0_svc+0x24/0x38 [ 53.526362] el0_svc+0x28/0xb8 [ 53.529407] el0t_64_sync_handler+0x134/0x150 [ 53.533751] el0t_64_sync+0x14c/0x150 [ 53.537405] Code: ???????? ???????? ???????? ???????? (????????) [ 53.543485] ---[ end trace 0000000000000000 ]--- Callers of __i2c_transfer() must verify that master_xfer is not NULL. Check that before i2c_smbus_xfer_emulated() call. Signed-off-by: Baruch Siach <baruch@tkos.co.il> --- drivers/i2c/i2c-core-smbus.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-)