On Fri, Mar 28, 2025 at 08:14:41AM -0600, Mathieu Poirier wrote: >On Fri, Mar 28, 2025 at 12:50:12PM +0800, Peng Fan wrote: >> On Thu, Mar 27, 2025 at 11:46:33AM -0600, Mathieu Poirier wrote: >> >Hi, >> > >> >On Wed, Mar 26, 2025 at 10:02:14AM +0800, Peng Fan (OSS) wrote: >> >> From: Peng Fan <peng....@nxp.com> >> >> >> >> There is case as below could trigger kernel dump: >> >> Use U-Boot to start remote processor(rproc) with resource table >> >> published to a fixed address by rproc. After Kernel boots up, >> >> stop the rproc, load a new firmware which doesn't have resource table >> >> ,and start rproc. >> >> >> > >> >If a firwmare image doesn't have a resouce table, rproc_elf_load_rsc_table() >> >will return an error [1], rproc_fw_boot() will exit prematurely [2] and the >> >remote processor won't be started. What am I missing? >> >> STM32 and i.MX use their own parse_fw implementation which allows no resource >> table: >> https://elixir.bootlin.com/linux/v6.13.7/source/drivers/remoteproc/stm32_rproc.c#L272 >> https://elixir.bootlin.com/linux/v6.13.7/source/drivers/remoteproc/imx_rproc.c#L598 > >Ok, that settles rproc_fw_boot() but there is also >rproc_find_loaded_rsc_table() >that will return NULL if a resource table is not found and preventing the >memcpy() in rproc_start() from happening: > >https://elixir.bootlin.com/linux/v6.14-rc6/source/drivers/remoteproc/remoteproc_core.c#L1288
Sorry, I forgot to mention below code: loaded_table is a valid pointer for i.MX, see https://elixir.bootlin.com/linux/v6.14-rc6/source/drivers/remoteproc/imx_rproc.c#L666, So loaded_table is valid, it is memcpy trigger kernel panic because table_sz is not zero while cached_table is NULL. loaded_table = rproc_find_loaded_rsc_table(rproc, fw); if (loaded_table) { memcpy(loaded_table, rproc->cached_table, rproc->table_sz); rproc->table_ptr = loaded_table; } Thanks, Peng > >> >> Thanks, >> Peng >> >> > >> >[1]. >> >https://elixir.bootlin.com/linux/v6.14-rc6/source/drivers/remoteproc/remoteproc_elf_loader.c#L338 >> >[2]. >> >https://elixir.bootlin.com/linux/v6.14-rc6/source/drivers/remoteproc/remoteproc_core.c#L1411 >> > >> > >> >> When starting rproc with a firmware not have resource table, >> >> `memcpy(loaded_table, rproc->cached_table, rproc->table_sz)` will >> >> trigger dump, because rproc->cache_table is set to NULL during the last >> >> stop operation, but rproc->table_sz is still valid. >> >> >> >> This issue is found on i.MX8MP and i.MX9. >> >> >> >> Dump as below: >> >> Unable to handle kernel NULL pointer dereference at virtual address >> >> 0000000000000000 >> >> Mem abort info: >> >> ESR = 0x0000000096000004 >> >> EC = 0x25: DABT (current EL), IL = 32 bits >> >> SET = 0, FnV = 0 >> >> EA = 0, S1PTW = 0 >> >> FSC = 0x04: level 0 translation fault >> >> Data abort info: >> >> ISV = 0, ISS = 0x00000004, ISS2 = 0x00000000 >> >> CM = 0, WnR = 0, TnD = 0, TagAccess = 0 >> >> GCS = 0, Overlay = 0, DirtyBit = 0, Xs = 0 >> >> user pgtable: 4k pages, 48-bit VAs, pgdp=000000010af63000 >> >> [0000000000000000] pgd=0000000000000000, p4d=0000000000000000 >> >> Internal error: Oops: 0000000096000004 [#1] PREEMPT SMP >> >> Modules linked in: >> >> CPU: 2 UID: 0 PID: 1060 Comm: sh Not tainted >> >> 6.14.0-rc7-next-20250317-dirty #38 >> >> Hardware name: NXP i.MX8MPlus EVK board (DT) >> >> pstate: a0000005 (NzCv daif -PAN -UAO -TCO -DIT -SSBS BTYPE=--) >> >> pc : __pi_memcpy_generic+0x110/0x22c >> >> lr : rproc_start+0x88/0x1e0 >> >> Call trace: >> >> __pi_memcpy_generic+0x110/0x22c (P) >> >> rproc_boot+0x198/0x57c >> >> state_store+0x40/0x104 >> >> dev_attr_store+0x18/0x2c >> >> sysfs_kf_write+0x7c/0x94 >> >> kernfs_fop_write_iter+0x120/0x1cc >> >> vfs_write+0x240/0x378 >> >> ksys_write+0x70/0x108 >> >> __arm64_sys_write+0x1c/0x28 >> >> invoke_syscall+0x48/0x10c >> >> el0_svc_common.constprop.0+0xc0/0xe0 >> >> do_el0_svc+0x1c/0x28 >> >> el0_svc+0x30/0xcc >> >> el0t_64_sync_handler+0x10c/0x138 >> >> el0t_64_sync+0x198/0x19c >> >> >> >> Clear rproc->table_sz to address the issue. >> >> >> >> While at here, also clear rproc->table_sz when rproc_fw_boot and >> >> rproc_detach. >> >> >> >> Fixes: 9dc9507f1880 ("remoteproc: Properly deal with the resource table >> >> when detaching") >> >> Signed-off-by: Peng Fan <peng....@nxp.com> >> >> --- >> >> >> >> V2: >> >> Clear table_sz when rproc_fw_boot and rproc_detach per Arnaud >> >> >> >> drivers/remoteproc/remoteproc_core.c | 3 +++ >> >> 1 file changed, 3 insertions(+) >> >> >> >> diff --git a/drivers/remoteproc/remoteproc_core.c >> >> b/drivers/remoteproc/remoteproc_core.c >> >> index c2cf0d277729..1efa53d4e0c3 100644 >> >> --- a/drivers/remoteproc/remoteproc_core.c >> >> +++ b/drivers/remoteproc/remoteproc_core.c >> >> @@ -1442,6 +1442,7 @@ static int rproc_fw_boot(struct rproc *rproc, const >> >> struct firmware *fw) >> >> kfree(rproc->cached_table); >> >> rproc->cached_table = NULL; >> >> rproc->table_ptr = NULL; >> >> + rproc->table_sz = 0; >> >> unprepare_rproc: >> >> /* release HW resources if needed */ >> >> rproc_unprepare_device(rproc); >> >> @@ -2025,6 +2026,7 @@ int rproc_shutdown(struct rproc *rproc) >> >> kfree(rproc->cached_table); >> >> rproc->cached_table = NULL; >> >> rproc->table_ptr = NULL; >> >> + rproc->table_sz = 0; >> >> out: >> >> mutex_unlock(&rproc->lock); >> >> return ret; >> >> @@ -2091,6 +2093,7 @@ int rproc_detach(struct rproc *rproc) >> >> kfree(rproc->cached_table); >> >> rproc->cached_table = NULL; >> >> rproc->table_ptr = NULL; >> >> + rproc->table_sz = 0; >> >> out: >> >> mutex_unlock(&rproc->lock); >> >> return ret; >> >> -- >> >> 2.37.1 >> >> >> > >
