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authorAndre Przywara <andre.przywara@arm.com>2024-01-26 15:23:25 +0300
committerSudeep Holla <sudeep.holla@arm.com>2024-02-20 09:35:54 +0300
commitf1d71576d2c9ec8fdb822173fa7f3de79475e9bd (patch)
treecdaa7635c803ef1d5a815fafb1e4f88a96d42928 /drivers/firmware/arm_scmi
parentdc36561e1548a8ca93b34ef385da03c289ec5ac0 (diff)
downloadlinux-f1d71576d2c9ec8fdb822173fa7f3de79475e9bd.tar.xz
firmware: arm_scmi: Fix double free in SMC transport cleanup path
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 within the given SCMI transport implementation. In this case, it is SMC transport. This will lead to a NULL pointer dereference at the second time: | scmi_protocol scmi_dev.1: Enabled polling mode TX channel - prot_id:16 | arm-scmi firmware:scmi: SCMI Notifications - Core Enabled. | arm-scmi firmware:scmi: unable to communicate with SCMI | 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=0000000881ef8000 | [0000000000000000] pgd=0000000000000000, p4d=0000000000000000 | Internal error: Oops: 0000000096000004 [#1] PREEMPT SMP | Modules linked in: | CPU: 4 PID: 1 Comm: swapper/0 Not tainted 6.7.0-rc2-00124-g455ef3d016c9-dirty #793 | Hardware name: FVP Base RevC (DT) | pstate: 61400009 (nZCv daif +PAN -UAO -TCO +DIT -SSBS BTYPE=--) | pc : smc_chan_free+0x3c/0x6c | lr : smc_chan_free+0x3c/0x6c | Call trace: | smc_chan_free+0x3c/0x6c | idr_for_each+0x68/0xf8 | scmi_cleanup_channels.isra.0+0x2c/0x58 | scmi_probe+0x434/0x734 | platform_probe+0x68/0xd8 | really_probe+0x110/0x27c | __driver_probe_device+0x78/0x12c | driver_probe_device+0x3c/0x118 | __driver_attach+0x74/0x128 | bus_for_each_dev+0x78/0xe0 | driver_attach+0x24/0x30 | bus_add_driver+0xe4/0x1e8 | driver_register+0x60/0x128 | __platform_driver_register+0x28/0x34 | scmi_driver_init+0x84/0xc0 | do_one_initcall+0x78/0x33c | kernel_init_freeable+0x2b8/0x51c | kernel_init+0x24/0x130 | ret_from_fork+0x10/0x20 | Code: f0004701 910a0021 aa1403e5 97b91c70 (b9400280) | ---[ end trace 0000000000000000 ]--- 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") Reviewed-by: Cristian Marussi <cristian.marussi@arm.com> Link: https://lore.kernel.org/r/20240126122325.2039669-1-andre.przywara@arm.com Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
Diffstat (limited to 'drivers/firmware/arm_scmi')
-rw-r--r--drivers/firmware/arm_scmi/smc.c7
1 files changed, 7 insertions, 0 deletions
diff --git a/drivers/firmware/arm_scmi/smc.c b/drivers/firmware/arm_scmi/smc.c
index 7611e9665038..39936e1dd30e 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);