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| author | Anshuman Khandual <khandual@linux.vnet.ibm.com> | 2018-03-29 11:53:37 +0530 |
|---|---|---|
| committer | Michael Ellerman <mpe@ellerman.id.au> | 2018-04-10 11:23:23 +1000 |
| commit | 709b973c844c0b4d115ac3a227a2e5a68722c912 (patch) | |
| tree | 003f922542c606be3d9ede19c0e14e9172f6e8e3 | |
| parent | 501a78cbc17c329fabf8e9750a1e9ab810c88a0e (diff) | |
| download | linux-stable-709b973c844c0b4d115ac3a227a2e5a68722c912.tar.gz linux-stable-709b973c844c0b4d115ac3a227a2e5a68722c912.tar.bz2 linux-stable-709b973c844c0b4d115ac3a227a2e5a68722c912.zip | |
powerpc/fscr: Enable interrupts earlier before calling get_user()
The function get_user() can sleep while trying to fetch instruction
from user address space and causes the following warning from the
scheduler.
BUG: sleeping function called from invalid context
Though interrupts get enabled back but it happens bit later after
get_user() is called. This change moves enabling these interrupts
earlier covering the function get_user(). While at this, lets check
for kernel mode and crash as this interrupt should not have been
triggered from the kernel context.
Signed-off-by: Anshuman Khandual <khandual@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
| -rw-r--r-- | arch/powerpc/kernel/traps.c | 32 |
1 files changed, 17 insertions, 15 deletions
diff --git a/arch/powerpc/kernel/traps.c b/arch/powerpc/kernel/traps.c index a2ef0c0e6c31..0904492e7032 100644 --- a/arch/powerpc/kernel/traps.c +++ b/arch/powerpc/kernel/traps.c @@ -1613,6 +1613,22 @@ void facility_unavailable_exception(struct pt_regs *regs) value = mfspr(SPRN_FSCR); status = value >> 56; + if ((hv || status >= 2) && + (status < ARRAY_SIZE(facility_strings)) && + facility_strings[status]) + facility = facility_strings[status]; + + /* We should not have taken this interrupt in kernel */ + if (!user_mode(regs)) { + pr_emerg("Facility '%s' unavailable (%d) exception in kernel mode at %lx\n", + facility, status, regs->nip); + die("Unexpected facility unavailable exception", regs, SIGABRT); + } + + /* We restore the interrupt state now */ + if (!arch_irq_disabled_regs(regs)) + local_irq_enable(); + if (status == FSCR_DSCR_LG) { /* * User is accessing the DSCR register using the problem @@ -1679,25 +1695,11 @@ void facility_unavailable_exception(struct pt_regs *regs) return; } - if ((hv || status >= 2) && - (status < ARRAY_SIZE(facility_strings)) && - facility_strings[status]) - facility = facility_strings[status]; - - /* We restore the interrupt state now */ - if (!arch_irq_disabled_regs(regs)) - local_irq_enable(); - pr_err_ratelimited("%sFacility '%s' unavailable (%d), exception at 0x%lx, MSR=%lx\n", hv ? "Hypervisor " : "", facility, status, regs->nip, regs->msr); out: - if (user_mode(regs)) { - _exception(SIGILL, regs, ILL_ILLOPC, regs->nip); - return; - } - - die("Unexpected facility unavailable exception", regs, SIGABRT); + _exception(SIGILL, regs, ILL_ILLOPC, regs->nip); } #endif |