4.4-stable review patch. If anyone has any objections, please let me know.
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[ Upstream commit 79c2206d369b87b19ac29cb47601059b6bf5c291 ]
An affected screen resolution is 1366 x 768, which width is not divisible by 8, the default font width. On such screens, when longer lines are earlyprintk'ed, overflow-to-next-line can never trigger, due to the left-most x-coordinate of the next character always less than the screen width. Earlyprintk will infinite loop in trying to print the rest of the string but unable to, due to the line being full.
This patch makes the trigger consider the right-most x-coordinate, instead of left-most, as the value to compare against the screen width threshold.
Signed-off-by: YiFei Zhu zhuyifei1999@gmail.com Signed-off-by: Ard Biesheuvel ard.biesheuvel@linaro.org Cc: Andy Lutomirski luto@kernel.org Cc: Arend van Spriel arend.vanspriel@broadcom.com Cc: Bhupesh Sharma bhsharma@redhat.com Cc: Borislav Petkov bp@alien8.de Cc: Dave Hansen dave.hansen@intel.com Cc: Eric Snowberg eric.snowberg@oracle.com Cc: Hans de Goede hdegoede@redhat.com Cc: Joe Perches joe@perches.com Cc: Jon Hunter jonathanh@nvidia.com Cc: Julien Thierry julien.thierry@arm.com Cc: Linus Torvalds torvalds@linux-foundation.org Cc: Marc Zyngier marc.zyngier@arm.com Cc: Matt Fleming matt@codeblueprint.co.uk Cc: Nathan Chancellor natechancellor@gmail.com Cc: Peter Zijlstra peterz@infradead.org Cc: Sai Praneeth Prakhya sai.praneeth.prakhya@intel.com Cc: Sedat Dilek sedat.dilek@gmail.com Cc: Thomas Gleixner tglx@linutronix.de Cc: linux-efi@vger.kernel.org Link: http://lkml.kernel.org/r/20181129171230.18699-12-ard.biesheuvel@linaro.org Signed-off-by: Ingo Molnar mingo@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- arch/x86/platform/efi/early_printk.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/x86/platform/efi/early_printk.c b/arch/x86/platform/efi/early_printk.c index 524142117296..82324fc25d5e 100644 --- a/arch/x86/platform/efi/early_printk.c +++ b/arch/x86/platform/efi/early_printk.c @@ -179,7 +179,7 @@ early_efi_write(struct console *con, const char *str, unsigned int num) num--; }
- if (efi_x >= si->lfb_width) { + if (efi_x + font->width > si->lfb_width) { efi_x = 0; efi_y += font->height; }