Hi, On Mon, Mar 18, 2024 at 04:24:46PM +0800, Youwan Wang wrote: > fix crash because of null pointers > > [ 190.538113] kernel NULL pointer dereference at virtual address 0000000000000000 > [ 190.538115] Mem abort info: > [ 190.538116] ESR = 0x96000004 > [ 190.538118] Exception class = DABT (current EL), IL = 32 bits > [ 190.538119] SET = 0, FnV = 0 > [ 190.538120] EA = 0, S1PTW = 0 > [ 190.538121] Data abort info: > [ 190.538122] ISV = 0, ISS = 0x00000004 > [ 190.538123] CM = 0, WnR = 0 > [ 190.538125] user pgtable: 4k pages, 48-bit VAs, pgdp = 00000000cf937cf2 > [ 190.538126] [0000000000000000] pgd=0000000000000000 > [ 190.538129] Internal error: Oops: 96000004 [#1] SMP > [ 190.538172] Process swapper/0 (pid: 0, stack limit = 0x000000000179ba77) > [ 190.538175] CPU: 0 PID: 0 Comm: swapper/0 Kdump: loaded Tainted: G > [ 190.538178] pstate: 40000085 (nZcv daIf -PAN -UAO) > [ 190.538183] pc : i2c_dw_isr+0x2e4/0x614 [i2c_designware_core] > [ 190.538185] lr : i2c_dw_isr+0x9c/0x614 [i2c_designware_core] > [ 190.538186] sp : ffff000008003e40 > [ 190.538187] x29: ffff000008003e40 x28: ffffd9cfad997200 > [ 190.538189] x27: ffff5f18a4f2c018 x26: 0000000000000000 > [ 190.538191] x25: ffff5f18a52d9fe8 x24: 0000000000000010 > [ 190.538193] x23: 0000000000000000 x22: 0000000000000000 > [ 190.538194] x21: 0000000000000510 x20: 0000000000000000 > [ 190.538196] x19: ffffd9cfa08d6080 x18: 00000000fffffffe > [ 190.538197] x17: 0000000000000000 x16: 0000000000000000 > [ 190.538199] x15: 0000000000000000 x14: 0000000000000000 > [ 190.538200] x13: 0000000000000000 x12: 000000000000028d > [ 190.538202] x11: 0000000000000040 x10: ffff5f18a52fe340 > [ 190.538203] x9 : ffffd9cfaf4a28f0 x8 : 0000000000000000 > [ 190.538205] x7 : ffffd9cfaf401b88 x6 : ffffd9cfaf401b60 > [ 190.538206] x5 : 0000000000000000 x4 : 0000000000000000 > [ 190.538208] x3 : 0000000000000000 x2 : ffff000008125000 > [ 190.538209] x1 : 0000000000000000 x0 : 0000000000000000 > [ 190.538211] Call trace: > [ 190.538213] i2c_dw_isr+0x2e4/0x614 [i2c_designware_core] > [ 190.538218] __handle_irq_event_percpu+0x68/0x230 > [ 190.538219] handle_irq_event+0x6c/0x130 > [ 190.538222] handle_fasteoi_irq+0xc0/0x220 > [ 190.538223] __handle_domain_irq+0x80/0xe0 > [ 190.538226] gic_handle_irq+0x84/0x188 > [ 190.538227] el1_irq+0xb0/0x140 > [ 190.538229] arch_cpu_idle+0x38/0x1c0 > [ 190.538232] do_idle+0x238/0x2a4 > [ 190.538234] cpu_startup_entry+0x2c/0x50 > [ 190.538237] rest_init+0xbc/0xc8 > [ 190.538240] start_kernel+0x4a8/0x4dc > [ 190.538242] Code: 937c7c80 b940727a 8b0002c1 f9403e77 (78606ac0) > [ 190.538248] SMP: stopping secondary CPUs > [ 190.538400] Starting crashdump kernel... > [ 190.538406] Bye! > > Signed-off-by: Youwan Wang <youwan@xxxxxxxxxxxx> > --- > drivers/i2c/busses/i2c-designware-master.c | 7 ++++++- > 1 file changed, 6 insertions(+), 1 deletion(-) > > diff --git a/drivers/i2c/busses/i2c-designware-master.c b/drivers/i2c/busses/i2c-designware-master.c > index ca1035e010c7..849e8a3e85ed 100644 > --- a/drivers/i2c/busses/i2c-designware-master.c > +++ b/drivers/i2c/busses/i2c-designware-master.c > @@ -429,12 +429,17 @@ i2c_dw_xfer_msg(struct dw_i2c_dev *dev) > struct i2c_msg *msgs = dev->msgs; > u32 intr_mask; > int tx_limit, rx_limit; > - u32 addr = msgs[dev->msg_write_idx].addr; > + u32 addr; > u32 buf_len = dev->tx_buf_len; > u8 *buf = dev->tx_buf; > bool need_restart = false; > unsigned int flr; > > + if (WARN_ON(!msgs)) > + return; Instead of treating the symptom, I suggest figuring out why this happens in the first place. If the controller interrupt is enabled and triggered it is expected that there is some transfer going on and dev->msgs != NULL.
