The gcc plugin -fanalyzer [1] tries to detect various
patterns of incorrect behaviour. The tool reports
arch/x86/kernel/apic/io_apic.c: In function ‘ioapic_destroy_irqdomain’:
arch/x86/kernel/apic/io_apic.c:2390:12: warning: check of ‘ioapics[idx].irqdomain’ for NULL after already dereferencing it [-Wanalyzer-deref-before-check]
|
| 2388 | struct fwnode_handle *fn = ioapics[idx].irqdomain->fwnode;
| | ^~
| | |
| | (1) pointer ‘ioapics[idx].irqdomain’ is dereferenced here
| 2389 |
| 2390 | if (ioapics[idx].irqdomain) {
| | ~
| | |
| | (2) pointer ‘ioapics[idx].irqdomain’ is checked for NULL here but it was already dereferenced at (1)
|
Fix the null dereference check in ioapic_destroy_irqdomain().
[1] https://gcc.gnu.org/onlinedocs/gcc-10.1.0/gcc/Static-Analyzer-Options.html
Signed-off-by: Prarit Bhargava <[email protected]>
CC: Thomas Gleixner <[email protected]>
CC: Ingo Molnar <[email protected]>
CC: Borislav Petkov <[email protected]>
CC: Dave Hansen <[email protected]>
CC: [email protected]
CC: "H. Peter Anvin" <[email protected]>
CC: "Peter Zijlstra (Intel)" <[email protected]>
CC: Wei Liu <[email protected]>
CC: Prarit Bhargava <[email protected]>
CC: Saurabh Sengar <[email protected]>
CC: Johan Hovold <[email protected]>
CC: Michael Kelley <[email protected]>
CC: David Malcolm <[email protected]>
CC: David Arcari <[email protected]>
CC: Don Zickus <[email protected]>
Signed-off-by: Prarit Bhargava <[email protected]>
---
arch/x86/kernel/apic/io_apic.c | 14 +++++++-------
1 file changed, 7 insertions(+), 7 deletions(-)
diff --git a/arch/x86/kernel/apic/io_apic.c b/arch/x86/kernel/apic/io_apic.c
index 00da6cf6b07d..f6f19eee0339 100644
--- a/arch/x86/kernel/apic/io_apic.c
+++ b/arch/x86/kernel/apic/io_apic.c
@@ -2381,14 +2381,14 @@ static int mp_irqdomain_create(int ioapic)
static void ioapic_destroy_irqdomain(int idx)
{
struct ioapic_domain_cfg *cfg = &ioapics[idx].irqdomain_cfg;
- struct fwnode_handle *fn = ioapics[idx].irqdomain->fwnode;
- if (ioapics[idx].irqdomain) {
- irq_domain_remove(ioapics[idx].irqdomain);
- if (!cfg->dev)
- irq_domain_free_fwnode(fn);
- ioapics[idx].irqdomain = NULL;
- }
+ if (!ioapics[idx].irqdomain)
+ return;
+
+ irq_domain_remove(ioapics[idx].irqdomain);
+ if (!cfg->dev)
+ irq_domain_free_fwnode(ioapics[idx].irqdomain->fwnode);
+ ioapics[idx].irqdomain = NULL;
}
void __init setup_IO_APIC(void)
--
2.43.0