Date: Sat, 6 Aug 2016 23:52:09 +0000 (UTC) From: John Baldwin <jhb@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-stable@freebsd.org, svn-src-stable-11@freebsd.org Subject: svn commit: r303807 - stable/11/sys/dev/fb Message-ID: <201608062352.u76Nq9aN044732@repo.freebsd.org>
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Author: jhb Date: Sat Aug 6 23:52:09 2016 New Revision: 303807 URL: https://svnweb.freebsd.org/changeset/base/303807 Log: MFC 303076,303225: Use MTX_SYSINIT for the VESA lock. 303076: vesa: fix panic on suspend Fix the following panic seen when migrating a FreeBSD guest on Xen: panic: mtx_lock() of destroyed mutex @ /usr/src/sys/dev/fb/vesa.c:541 cpuid = 0 KDB: stack backtrace: db_trace_self_wrapper() at db_trace_self_wrapper+0x2b/frame 0xfffffe001d2fa4f0 vpanic() at vpanic+0x182/frame 0xfffffe001d2fa570 kassert_panic() at kassert_panic+0x126/frame 0xfffffe001d2fa5e0 __mtx_lock_flags() at __mtx_lock_flags+0x15b/frame 0xfffffe001d2fa630 vesa_bios_save_restore() at vesa_bios_save_restore+0x78/frame 0xfffffe001d2fa680 vga_suspend() at vga_suspend+0xa3/frame 0xfffffe001d2fa6b0 isavga_suspend() at isavga_suspend+0x1d/frame 0xfffffe001d2fa6d0 bus_generic_suspend_child() at bus_generic_suspend_child+0x44/frame [...] This is caused because vga_sub_configure (which is called if the VGA adapter is attached after VESA tried to initialize), points to vesa_configure, which doesn't initialize the VESA mutex. In order to fix it, make sure vga_sub_configure points to vesa_load, so that all the needed vesa components are properly initialized. 303225: Use MTX_SYSINIT for the VESA lock. vesa_init_done isn't a reliable guard for the mutex init. If vesa_configure() doesn't find valid VESA info it will not set vesa_init_done, but the lock will remain initialized. Revert r303076 and use MTX_SYSINIT to deterministically init the lock. PR: 209203 Approved by: re (gjb) Modified: stable/11/sys/dev/fb/vesa.c Directory Properties: stable/11/ (props changed) Modified: stable/11/sys/dev/fb/vesa.c ============================================================================== --- stable/11/sys/dev/fb/vesa.c Sat Aug 6 20:27:12 2016 (r303806) +++ stable/11/sys/dev/fb/vesa.c Sat Aug 6 23:52:09 2016 (r303807) @@ -79,6 +79,7 @@ struct adp_state { typedef struct adp_state adp_state_t; static struct mtx vesa_lock; +MTX_SYSINIT(vesa_lock, &vesa_lock, "VESA lock", MTX_DEF); static int vesa_state; static void *vesa_state_buf; @@ -1914,8 +1915,6 @@ vesa_load(void) if (vesa_init_done) return (0); - mtx_init(&vesa_lock, "VESA lock", NULL, MTX_DEF); - /* locate a VGA adapter */ vesa_adp = NULL; error = vesa_configure(0); @@ -1954,7 +1953,6 @@ vesa_unload(void) } vesa_bios_uninit(); - mtx_destroy(&vesa_lock); return (error); }
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