| Message ID | 20240126122325.2039669-1-andre.przywara@arm.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | firmware: arm_scmi: fix double free in smc cleanup path | expand |
On Fri, Jan 26, 2024 at 12:23:25PM +0000, Andre Przywara wrote: > When the generic SCMI code tears down a channel, it calls the chan_free > callback function, defined by each transport. Since multiple protocols > might share the same transport_info member, chan_free() might want to > clean up the same member multiple times. This will lead to a NULL > pointer dereference at the second time: Hi Andre, thanks for this. > > [ 9.788824] scmi_protocol scmi_dev.1: Enabled polling mode TX channel - prot_id:16 > [ 9.813091] arm-scmi firmware:scmi: SCMI Notifications - Core Enabled. > [ 9.814485] arm-scmi firmware:scmi: unable to communicate with SCMI > [ 9.824996] Unable to handle kernel NULL pointer dereference at virtual address 0000000000000000 > [ 9.825586] Mem abort info: > [ 9.825863] ESR = 0x0000000096000004 > [ 9.826193] EC = 0x25: DABT (current EL), IL = 32 bits > [ 9.827625] SET = 0, FnV = 0 > [ 9.827927] EA = 0, S1PTW = 0 > [ 9.828232] FSC = 0x04: level 0 translation fault > [ 9.828628] Data abort info: > [ 9.828909] ISV = 0, ISS = 0x00000004, ISS2 = 0x00000000 > [ 9.829333] CM = 0, WnR = 0, TnD = 0, TagAccess = 0 > [ 9.829745] GCS = 0, Overlay = 0, DirtyBit = 0, Xs = 0 > [ 9.830170] user pgtable: 4k pages, 48-bit VAs, pgdp=0000000881ef8000 > [ 9.830887] [0000000000000000] pgd=0000000000000000, p4d=0000000000000000 > [ 9.831763] Internal error: Oops: 0000000096000004 [#1] PREEMPT SMP > [ 9.832177] Modules linked in: > [ 9.832440] CPU: 4 PID: 1 Comm: swapper/0 Not tainted 6.7.0-rc2-00124-g455ef3d016c9-dirty #793 > [ 9.832997] Hardware name: FVP Base RevC (DT) > [ 9.833302] pstate: 61400009 (nZCv daif +PAN -UAO -TCO +DIT -SSBS BTYPE=--) > [ 9.833775] pc : smc_chan_free+0x3c/0x6c > [ 9.834089] lr : smc_chan_free+0x3c/0x6c > [ 9.834401] sp : ffff8000839bba00 > [ 9.834652] x29: ffff8000839bba00 x28: 00000000ffffffa1 x27: ffff0008024aa350 > [ 9.835227] x26: ffff800083305898 x25: ffff0008004d4a18 x24: ffff000800328000 > [ 9.835804] x23: ffff0008024aa1b0 x22: 0000000000000000 x21: 000000007fffffff > [ 9.836375] x20: 0000000000000000 x19: ffff000802639440 x18: 0000000000000010 > [ 9.836945] x17: 73203e3d20293062 x16: 3161613432303830 x15: 303066666666202c > [ 9.837522] x14: 00000000000001f4 x13: ffff000800328488 x12: 00000000ffffffea > [ 9.838094] x11: 00000000ffff7fff x10: 00000000ffff7fff x9 : ffff800082f3b430 > [ 9.838667] x8 : 00000000000bffe8 x7 : c0000000ffff7fff x6 : 000000000005fff4 > [ 9.839237] x5 : 00000000002bffa8 x4 : 0000000000000000 x3 : 0000000000000000 > [ 9.839803] x2 : 0000000000000000 x1 : 0000000000000000 x0 : 000000000000004a > [ 9.840368] Call trace: > [ 9.840571] smc_chan_free+0x3c/0x6c > [ 9.840868] idr_for_each+0x68/0xf8 > [ 9.841164] scmi_cleanup_channels.isra.0+0x2c/0x58 > [ 9.841543] scmi_probe+0x434/0x734 > [ 9.841848] platform_probe+0x68/0xd8 > [ 9.842164] really_probe+0x110/0x27c > [ 9.842464] __driver_probe_device+0x78/0x12c > [ 9.842801] driver_probe_device+0x3c/0x118 > [ 9.843130] __driver_attach+0x74/0x128 > [ 9.843439] bus_for_each_dev+0x78/0xe0 > [ 9.843783] driver_attach+0x24/0x30 > [ 9.844121] bus_add_driver+0xe4/0x1e8 > [ 9.844466] driver_register+0x60/0x128 > [ 9.844778] __platform_driver_register+0x28/0x34 > [ 9.845149] scmi_driver_init+0x84/0xc0 > [ 9.845459] do_one_initcall+0x78/0x33c > [ 9.845778] kernel_init_freeable+0x2b8/0x51c > [ 9.846127] kernel_init+0x24/0x130 > [ 9.846426] ret_from_fork+0x10/0x20 > [ 9.846772] Code: f0004701 910a0021 aa1403e5 97b91c70 (b9400280) > [ 9.847172] ---[ end trace 0000000000000000 ]--- > [ 9.847604] Kernel panic - not syncing: Attempted to kill init! exitcode=0x0000000b > > Simply check for the struct pointer being NULL before trying to access > its members, to avoid this situation. > This was found when a transport doesn't really work (for instance no SMC > service), the probe routines then tries to clean up, and triggers a crash. > > Signed-off-by: Andre Przywara <andre.przywara@arm.com> > Fixes: 1dc6558062da ("firmware: arm_scmi: Add smc/hvc transport") LGTM, maybe explicitly saying in the commit message that it is an issue of the SMC transport would be better, but I think Sudeep can easily add such a remark without the need to post a V2. > --- > Hi, > > reportedly Cristian has some patches in the making that solve this > problem in a more general way, but meanwhile this is an easy backport > candidate. Yes, this fix is definitely needed as it is, beside any possible future improvement in the core. Reviewed-by: Cristian Marussi <cristian.marussi@arm.com> Thanks, Cristian
On Fri, 26 Jan 2024 12:23:25 +0000, Andre Przywara wrote: > When the generic SCMI code tears down a channel, it calls the chan_free > callback function, defined by each transport. Since multiple protocols > might share the same transport_info member, chan_free() might want to > clean up the same member multiple times. This will lead to a NULL > pointer dereference at the second time: > > [ 9.788824] scmi_protocol scmi_dev.1: Enabled polling mode TX channel - prot_id:16 > [ 9.813091] arm-scmi firmware:scmi: SCMI Notifications - Core Enabled. > [ 9.814485] arm-scmi firmware:scmi: unable to communicate with SCMI > [ 9.824996] Unable to handle kernel NULL pointer dereference at virtual address 0000000000000000 > [ 9.825586] Mem abort info: > [ 9.825863] ESR = 0x0000000096000004 > [ 9.826193] EC = 0x25: DABT (current EL), IL = 32 bits > [ 9.827625] SET = 0, FnV = 0 > [ 9.827927] EA = 0, S1PTW = 0 > [ 9.828232] FSC = 0x04: level 0 translation fault > [ 9.828628] Data abort info: > [ 9.828909] ISV = 0, ISS = 0x00000004, ISS2 = 0x00000000 > [ 9.829333] CM = 0, WnR = 0, TnD = 0, TagAccess = 0 > [ 9.829745] GCS = 0, Overlay = 0, DirtyBit = 0, Xs = 0 > [ 9.830170] user pgtable: 4k pages, 48-bit VAs, pgdp=0000000881ef8000 > [ 9.830887] [0000000000000000] pgd=0000000000000000, p4d=0000000000000000 > [ 9.831763] Internal error: Oops: 0000000096000004 [#1] PREEMPT SMP > [ 9.832177] Modules linked in: > [ 9.832440] CPU: 4 PID: 1 Comm: swapper/0 Not tainted 6.7.0-rc2-00124-g455ef3d016c9-dirty #793 > [ 9.832997] Hardware name: FVP Base RevC (DT) > [ 9.833302] pstate: 61400009 (nZCv daif +PAN -UAO -TCO +DIT -SSBS BTYPE=--) > [ 9.833775] pc : smc_chan_free+0x3c/0x6c > [ 9.834089] lr : smc_chan_free+0x3c/0x6c > [ 9.834401] sp : ffff8000839bba00 > [ 9.834652] x29: ffff8000839bba00 x28: 00000000ffffffa1 x27: ffff0008024aa350 > [ 9.835227] x26: ffff800083305898 x25: ffff0008004d4a18 x24: ffff000800328000 > [ 9.835804] x23: ffff0008024aa1b0 x22: 0000000000000000 x21: 000000007fffffff > [ 9.836375] x20: 0000000000000000 x19: ffff000802639440 x18: 0000000000000010 > [ 9.836945] x17: 73203e3d20293062 x16: 3161613432303830 x15: 303066666666202c > [ 9.837522] x14: 00000000000001f4 x13: ffff000800328488 x12: 00000000ffffffea > [ 9.838094] x11: 00000000ffff7fff x10: 00000000ffff7fff x9 : ffff800082f3b430 > [ 9.838667] x8 : 00000000000bffe8 x7 : c0000000ffff7fff x6 : 000000000005fff4 > [ 9.839237] x5 : 00000000002bffa8 x4 : 0000000000000000 x3 : 0000000000000000 > [ 9.839803] x2 : 0000000000000000 x1 : 0000000000000000 x0 : 000000000000004a > [ 9.840368] Call trace: > [ 9.840571] smc_chan_free+0x3c/0x6c > [ 9.840868] idr_for_each+0x68/0xf8 > [ 9.841164] scmi_cleanup_channels.isra.0+0x2c/0x58 > [ 9.841543] scmi_probe+0x434/0x734 > [ 9.841848] platform_probe+0x68/0xd8 > [ 9.842164] really_probe+0x110/0x27c > [ 9.842464] __driver_probe_device+0x78/0x12c > [ 9.842801] driver_probe_device+0x3c/0x118 > [ 9.843130] __driver_attach+0x74/0x128 > [ 9.843439] bus_for_each_dev+0x78/0xe0 > [ 9.843783] driver_attach+0x24/0x30 > [ 9.844121] bus_add_driver+0xe4/0x1e8 > [ 9.844466] driver_register+0x60/0x128 > [ 9.844778] __platform_driver_register+0x28/0x34 > [ 9.845149] scmi_driver_init+0x84/0xc0 > [ 9.845459] do_one_initcall+0x78/0x33c > [ 9.845778] kernel_init_freeable+0x2b8/0x51c > [ 9.846127] kernel_init+0x24/0x130 > [ 9.846426] ret_from_fork+0x10/0x20 > [ 9.846772] Code: f0004701 910a0021 aa1403e5 97b91c70 (b9400280) > [ 9.847172] ---[ end trace 0000000000000000 ]--- > [ 9.847604] Kernel panic - not syncing: Attempted to kill init! exitcode=0x0000000b > > [...] Applied to sudeep.holla/linux (for-next/scmi/updates), thanks! [1/1] firmware: arm_scmi: fix double free in smc cleanup path https://git.kernel.org/sudeep.holla/c/f1d71576d2c9 -- Regards, Sudeep
diff --git a/drivers/firmware/arm_scmi/smc.c b/drivers/firmware/arm_scmi/smc.c index 7611e9665038d..39936e1dd30e9 100644 --- a/drivers/firmware/arm_scmi/smc.c +++ b/drivers/firmware/arm_scmi/smc.c @@ -214,6 +214,13 @@ static int smc_chan_free(int id, void *p, void *data) struct scmi_chan_info *cinfo = p; struct scmi_smc *scmi_info = cinfo->transport_info; + /* + * Different protocols might share the same chan info, so a previous + * smc_chan_free call might have already freed the structure. + */ + if (!scmi_info) + return 0; + /* Ignore any possible further reception on the IRQ path */ if (scmi_info->irq > 0) free_irq(scmi_info->irq, scmi_info);
When the generic SCMI code tears down a channel, it calls the chan_free callback function, defined by each transport. Since multiple protocols might share the same transport_info member, chan_free() might want to clean up the same member multiple times. This will lead to a NULL pointer dereference at the second time: [ 9.788824] scmi_protocol scmi_dev.1: Enabled polling mode TX channel - prot_id:16 [ 9.813091] arm-scmi firmware:scmi: SCMI Notifications - Core Enabled. [ 9.814485] arm-scmi firmware:scmi: unable to communicate with SCMI [ 9.824996] Unable to handle kernel NULL pointer dereference at virtual address 0000000000000000 [ 9.825586] Mem abort info: [ 9.825863] ESR = 0x0000000096000004 [ 9.826193] EC = 0x25: DABT (current EL), IL = 32 bits [ 9.827625] SET = 0, FnV = 0 [ 9.827927] EA = 0, S1PTW = 0 [ 9.828232] FSC = 0x04: level 0 translation fault [ 9.828628] Data abort info: [ 9.828909] ISV = 0, ISS = 0x00000004, ISS2 = 0x00000000 [ 9.829333] CM = 0, WnR = 0, TnD = 0, TagAccess = 0 [ 9.829745] GCS = 0, Overlay = 0, DirtyBit = 0, Xs = 0 [ 9.830170] user pgtable: 4k pages, 48-bit VAs, pgdp=0000000881ef8000 [ 9.830887] [0000000000000000] pgd=0000000000000000, p4d=0000000000000000 [ 9.831763] Internal error: Oops: 0000000096000004 [#1] PREEMPT SMP [ 9.832177] Modules linked in: [ 9.832440] CPU: 4 PID: 1 Comm: swapper/0 Not tainted 6.7.0-rc2-00124-g455ef3d016c9-dirty #793 [ 9.832997] Hardware name: FVP Base RevC (DT) [ 9.833302] pstate: 61400009 (nZCv daif +PAN -UAO -TCO +DIT -SSBS BTYPE=--) [ 9.833775] pc : smc_chan_free+0x3c/0x6c [ 9.834089] lr : smc_chan_free+0x3c/0x6c [ 9.834401] sp : ffff8000839bba00 [ 9.834652] x29: ffff8000839bba00 x28: 00000000ffffffa1 x27: ffff0008024aa350 [ 9.835227] x26: ffff800083305898 x25: ffff0008004d4a18 x24: ffff000800328000 [ 9.835804] x23: ffff0008024aa1b0 x22: 0000000000000000 x21: 000000007fffffff [ 9.836375] x20: 0000000000000000 x19: ffff000802639440 x18: 0000000000000010 [ 9.836945] x17: 73203e3d20293062 x16: 3161613432303830 x15: 303066666666202c [ 9.837522] x14: 00000000000001f4 x13: ffff000800328488 x12: 00000000ffffffea [ 9.838094] x11: 00000000ffff7fff x10: 00000000ffff7fff x9 : ffff800082f3b430 [ 9.838667] x8 : 00000000000bffe8 x7 : c0000000ffff7fff x6 : 000000000005fff4 [ 9.839237] x5 : 00000000002bffa8 x4 : 0000000000000000 x3 : 0000000000000000 [ 9.839803] x2 : 0000000000000000 x1 : 0000000000000000 x0 : 000000000000004a [ 9.840368] Call trace: [ 9.840571] smc_chan_free+0x3c/0x6c [ 9.840868] idr_for_each+0x68/0xf8 [ 9.841164] scmi_cleanup_channels.isra.0+0x2c/0x58 [ 9.841543] scmi_probe+0x434/0x734 [ 9.841848] platform_probe+0x68/0xd8 [ 9.842164] really_probe+0x110/0x27c [ 9.842464] __driver_probe_device+0x78/0x12c [ 9.842801] driver_probe_device+0x3c/0x118 [ 9.843130] __driver_attach+0x74/0x128 [ 9.843439] bus_for_each_dev+0x78/0xe0 [ 9.843783] driver_attach+0x24/0x30 [ 9.844121] bus_add_driver+0xe4/0x1e8 [ 9.844466] driver_register+0x60/0x128 [ 9.844778] __platform_driver_register+0x28/0x34 [ 9.845149] scmi_driver_init+0x84/0xc0 [ 9.845459] do_one_initcall+0x78/0x33c [ 9.845778] kernel_init_freeable+0x2b8/0x51c [ 9.846127] kernel_init+0x24/0x130 [ 9.846426] ret_from_fork+0x10/0x20 [ 9.846772] Code: f0004701 910a0021 aa1403e5 97b91c70 (b9400280) [ 9.847172] ---[ end trace 0000000000000000 ]--- [ 9.847604] Kernel panic - not syncing: Attempted to kill init! exitcode=0x0000000b Simply check for the struct pointer being NULL before trying to access its members, to avoid this situation. This was found when a transport doesn't really work (for instance no SMC service), the probe routines then tries to clean up, and triggers a crash. Signed-off-by: Andre Przywara <andre.przywara@arm.com> Fixes: 1dc6558062da ("firmware: arm_scmi: Add smc/hvc transport") --- Hi, reportedly Cristian has some patches in the making that solve this problem in a more general way, but meanwhile this is an easy backport candidate. I am not 100% sure about the wording in the commit message, so feel free to correct me there. Cheers, Andre drivers/firmware/arm_scmi/smc.c | 7 +++++++ 1 file changed, 7 insertions(+)