| commit | 7b307d292ab26ef6a9b85754a608aa2b5b607318 | |
| author | Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> | |
| Sun, 24 May 2020 09:38:19 +0000 (24 15:08 +0530) | ||
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | |
| Wed, 24 Jun 2020 15:50:45 +0000 (24 17:50 +0200) | ||
| tree | ebf0e742b7d32e68a59b8ad3b6f80128aba46fad | treesnapshot (tar.gz zip) |
| parent | f651e94899ed08b1766bda30f410d33fdd3970ff | commitdiff |
powerpc: Fix kernel crash in show_instructions() w/DEBUG_VIRTUAL
[ Upstream commit a6e2c226c3d51fd93636320e47cabc8a8f0824c5 ]
With CONFIG_DEBUG_VIRTUAL=y, we can hit a BUG() if we take a hard
lockup watchdog interrupt when in OPAL mode.
This happens in show_instructions() if the kernel takes the watchdog
NMI IPI, or any other interrupt, with MSR_IR == 0. show_instructions()
updates the variable pc in the loop and the second iteration will
result in BUG().
We hit the BUG_ON due the below check in __va()
#define __va(x)
({
VIRTUAL_BUG_ON((unsigned long)(x) >= PAGE_OFFSET);
(void *)(unsigned long)((phys_addr_t)(x) | PAGE_OFFSET);
})
Fix it by moving the check out of the loop. Also update nip so that
the nip == pc check still matches.
Fixes: 4dd7554a6456 ("powerpc/64: Add VIRTUAL_BUG_ON checks for __va and __pa addresses")
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
[mpe: Use IS_ENABLED(), massage change log]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200524093822.423487-1-aneesh.kumar@linux.ibm.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit a6e2c226c3d51fd93636320e47cabc8a8f0824c5 ]
With CONFIG_DEBUG_VIRTUAL=y, we can hit a BUG() if we take a hard
lockup watchdog interrupt when in OPAL mode.
This happens in show_instructions() if the kernel takes the watchdog
NMI IPI, or any other interrupt, with MSR_IR == 0. show_instructions()
updates the variable pc in the loop and the second iteration will
result in BUG().
We hit the BUG_ON due the below check in __va()
#define __va(x)
({
VIRTUAL_BUG_ON((unsigned long)(x) >= PAGE_OFFSET);
(void *)(unsigned long)((phys_addr_t)(x) | PAGE_OFFSET);
})
Fix it by moving the check out of the loop. Also update nip so that
the nip == pc check still matches.
Fixes: 4dd7554a6456 ("powerpc/64: Add VIRTUAL_BUG_ON checks for __va and __pa addresses")
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
[mpe: Use IS_ENABLED(), massage change log]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200524093822.423487-1-aneesh.kumar@linux.ibm.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
| arch/powerpc/kernel/process.c | diffblobblamehistory |